Living in a safe predictable world

The underground ecotope is not only challenging, it is also quite safe from predators. Certainly, naked mole-rats would not be able to survive in any other ecotope than in the safe, humid, and ultraviolet-light-protected underground burrows. No wonder that convergent patterns can be seen also in life histories of subterranean mammals. They all show tendencies to K-strategy, breed rather slowly, have slow and long prenatal and postnatal development, slow rates of growth, and unusually long...

Domestic cat Felis silvestris f catus

The cat is one of the most recent domestic animals. In spite of its coexistence with humans, it still has an independent nature and the perfect hunting instincts of a solitary hunter. It is highly individualistic and should not have undergone successful domestication at all. The progenitor of the domestic cat is the African subspecies of wild cat (Felis silvestris lybica). Domestication of the cat occurred in Egypt from 4000 to 2000 B.C. Preserved cat mummies provide dometication evidence. The...

Glossary Terms For Mammals

Adaptive radiation Diversification of a species or single ancestral type into several forms that are each adaptively specialized to a specific niche. Agonistic Behavioral patterns that are aggressive in context. Allopatric Occurring in separate, nonoverlapping geographic areas. Alpha breeder The reproductively dominant member of a social unit. Altricial An adjective referring to a mammal that is born with little, if any, hair, is unable to feed itself, and initially has poor sensory and...

Resources

Mammalogy Adaptation, Diversity, and Ecology. San Francisco McGraw-Hill, 2003. Hildebrand, M. Analysis of Vertebrate Structure. 4th ed. New York John Wiley & Sons, 1994. MacDonald, D., ed. The Encyclopedia of Mammals. New York Facts on File, 2001. Martin, R. E., R. H. Pine, and A. F. DeBlase. A Manual of Mammalogy. 3rd ed. San Francisco McGraw-Hill, 2001. Neuweiler, G. The Biology of Bats. New York Oxford University Press, 2000. Novak, R. M. Walker's Mammals of the...

Mammalian reproduction

Reproduction is pivotal to the continuation of life. From an evolutionary standpoint, there is no single factor that has more impact on the development of species. The impetus to reproduce shapes morphology, physiology, life history, and behavior of all animals, mammals included. From the egg-laying platypus (Ornithorhynchus anatinus) to the wildebeests (genus Connochaetes) that have neonates that can run mere seconds after birth, a wide variety of strategies have evolved to successfully bear...

Distribution

Short-beaked echidnas are found throughout Australia and in some parts of New Guinea. Long-beaked echidnas occur only in New Guinea and Salawati. They once inhabited parts of Australia, but died out about 20,000 years ago. A short-beaked echidna (Tachyglossus aculeatus) feeds on termites. (Photo by Animals Animals K. Atkinson, OSF. Reproduced by permission.) A short-beaked echidna (Tachyglossus aculeatus) feeds on termites. (Photo by Animals Animals K. Atkinson, OSF. Reproduced by permission.)...

Tool use and construction

Tools can be defined as detached objects that are used to achieve a goal. Achievement of the goal can involve manipulation of some aspect of the environment, including another organism. The making of tools involves modifying some object in the environment for use as a tool, but not all objects used as tools by animals are constructed. Instances of tool use and tool construction have been observed in great apes and monkeys living in captivity. All species of great ape have been observed to make...

Enrichment

In addition to physical needs, a captive mammal has psychological needs that must be satisfied. Enrichment means the application of environmental stimuli in an attempt to cre- A gorilla (Gorilla gorilla) at the Frankfurt Zoo, Germany. The gorilla's native habitiat has been reduced in size by human expansion. Survival of the species is threatened, and zoos educate their visitors about the need to protect animal environments. (Photo by Bildarchiv Okapia Photo Researchers, Inc. Reproduced by...

Feral cats in Australia

A good example of the pest not-pest duality is the domestic cat on the island continent of Australia. Between 4 million and 18 million feral cats (Felis catus) live wild in Australia. Until recently most of these cats were believed to be descendants of European cats brought to the continent in the late eighteenth century, with a few earlier arrivals via trading ships and shipwrecks. However, Australia's aboriginal people regard cats as native. Genetic analysis indicates that Australian feral...

Why and how

We have to appreciate that the first breeders of domestic animals did not have any instructions and they were not able to imagine where domestication would lead. It is assumed that the initial reasons motivating domestication were frequently different from the animals' subsequent use. However, the main reason was very simply to access a supply of food. Exceptions are cats and dogs, which became partners to people, and later assumed many other roles, such as dogs becoming guardians. Even though...

Peculiar morphology The mammalian penis bone

A peculiar bony structure exists in the penis of many mammalian species, and this bone, often referred to as bac- ulum or os penis, is probably one of the most puzzling and least understood bones of the mammalian skeleton. Present in a variety of orders including Insectivora, Chiroptera, Primates, Rodentia, and Carnivora, this bone does not occur in all Orders in the Mammalia, but also does not occur in all species within each Order. Within a species the bone also varies in size, with older...

Conservation

Understanding the cognitive abilities of animals and how they use these capacities to solve daily problems of finding guage symbols and demonstrating numerical competence. The opportunity to observe an animal using complex cognitive abilities to solve a problem not only informs visitors of the capabilities of great apes, it also serves to illustrate the importance of preserving animals with such complex minds. A chimpanzee (Pan troglodytes) uses a stick to get termites in Sweet-waters Reserve,...

Peculiar mechanisms Inbreeding avoidance

Inbreeding is a word that describes breeding of one individual to another that is related, and in most animals, mammals included, is relatively rare. This is likely so because breeding with relatives has deleterious effects on the survival of the offspring, and often leads to reduced fertility. In evolution, inbreeding is rapidly selected against. Not surprisingly then, animals go to great lengths to avoid breeding with animals to whom they are related. To accomplish this, animals must be able...

Sexual maturity

Sexual maturity in many species occurs when body size reaches adult size. However, there are some notable exceptions male least weasels (Mustela nivalis) often seek maternity dens of females and will copulate the newly born females, as soon as 4 hours after birth. At that time, neonates still have their eyes and ears closed, are pink and hairless. This strategy enables females to have a first litter within weeks of birth (least weasels do not exhibit delayed implantation), and then again before...

Population management programs

Zoos worldwide have intensive conservation programs for mammals. Although the names and acronyms vary by the geographic region of zoo associations, their functions are very much the same. In North America, that plan is called the Species Survival Plan (SSP), a copyright name and program implemented in 1981 by the American Zoo and Aquarium Association (AZA). The Species Survival Plan is defined as a cooperative breeding and conservation program designed to maintain a genetically viable and...

Thermoregulation

Thermuregulation

Mammals produce their own body heat (endothermy) as opposed to absorbing energy from the outside environment. This metabolic heat is produced mainly in their mitochondria. Internal organs such as the heart, kidney, and brain are larger in mammals than reptiles and the corresponding increase in mitochondrial membrane surface area adds to their An agile bobcat (Lynx rufus) leaps across rocks. (Photo by Hans Reinhard. Bruce Coleman, Inc. Reproduced by permission.) An agile bobcat (Lynx rufus)...

Reindeer Rangifer tarandus

Not much is known about the domestication of the reindeer. It is assumed that it was domesticated at only one place in the Sayan mountains from 3000 to 1000 B.C. Chinese sources from the sixth century describe the reindeer as a domestic animal. The reindeer may have become used to humans when it came to human settlements to lick salt from human urine. It served in place of cattle and horses in harsh northern conditions. Domestic reindeer live in northern Eurasia and Canada. The Canadian caribou...

Coloring

One of the first signs of domestication is variability of color. The individuals all have white spots or all white or all black. It is interesting that white coloring is usually connected with lower performance (there are few white racing horses and even fewer winners) or with different defects (white noble cats have a high incidence of deafness). Sheep have been domesticated for both their meat and their wool. (Photo by Andris Apse. Bruce Coleman, Inc. Reproduced by permission.) Sheep have...

Conservation status

The platypus is a difficult animal to census or survey burrow entrances are generally well hidden and the animals rarely leave evidence of their activities in the forms of tracks, scats, or food scraps. Live-trapping nets are time consuming to set and must be monitored closely through the night. Accordingly, knowledge of how the species is faring is sketchy in many parts of its range. In broad terms, it is known that the platypus remains fairly common along some waterways, but The bill of a...

Placental mammals

Placental mammals constitute the largest group of mammals. In placental mammals, fertilized eggs migrate to the uterus or to the uterine horns where they implant and begin to develop. In the process, a placenta is grown to act as the interface between mother and offspring. The highly vascular placenta then connects to growing embryos via the umbilical cord, and exchanges of nutrients and waste between mother and fetus occur in the placenta as fluids are not shared between mother and fetus in...

Pigs threaten foxes

The case for removing feral pigs (Sus scrofa), has less opposition in the Channel Islands National Park and other islands off the coast of southern California. This is a case where one invasive exotic mammal species, the feral pig, has changed the ecological relationships among several native predators. On four islands, feral pigs introduced into the ecosystem are indirectly leading to the extinction of four subspecies of island fox (Urocyon littoralis), a tiny animal smaller in size than a...

Energy

Powered flight has enormous energy costs. Flight is energetically cheaper than walking or running once the bat is up in the air. However, it takes a considerable amount of calories to get airborne. Flying is very demanding on bat physiology. In some species, the heart rate may rise to approximately 1,000 beats per minute in order to supply oxygen to the tissues during flight. Because of these demands, the heart and lungs are larger in bats than in comparably sized mammals. Bats do not consume...

Dog Canis lupus f familiaris

The dog was the first domestic animal however, the beginning of its coexistence with humans is still unclear. The wolf (Canis lupus) is the progenitor of all domestic dog breeds and feral populations. Fifteen thousand years ago, the wolf lived in all of Eurasia, in north Africa, and in North and Central America. It evolved into many subspecies, which differ in size and color. The small Indian wolf (C. l. pallipes) and the larger Eurasian wolf (C. l. lupus) are the most likely dog ancestors....

Ontogeny and development

Mammalian ontogeny and development can, from a physiological standpoint, be separated into three general strategies. First, the monotremes such as platypus and echidnas are oviparous, meaning that they conceive young via copulation, but give birth to young inside an eggshell. After a short period of development in the egg, young hatch and then suckle the mother's milk as it leaks into the fur and not through a nipple as monotremes do not have nipples. In contrast, marsupials and placental...

Viruses for rabbit control

The myxoma virus was imported into Australia in 1936, and extensively studied before being released into the environment in 1950. The virulence of the myxoma virus is rated on a scale of one to five, with one being most virulent. The original myxoma virus strain released into the environment was rated one, and provided a spectacular 99 rabbit mortality when first released into the environment in the early 1950s. Without rabbits grazing on the landscape, the amount of forage available for sheep...

Gray foureyed opossum

Didelphis opossum (Linnaeus, 1758), Paramaribo, Surinam. OTHER COMMON NAMES French Opossum a quatre yeux German Vieraugenbeutel-ratte Spanish Tlacuache cuatro ojos, zorro cuatro ojos, comadreja cuatro ojos. Length 8-13 in (20-33 cm) weight 7-24.7 oz (200-700 g). This relatively large opossum has dense and relatively short hair that varies from pale gray to dark gray dorsally and yellowish white ventrally. The cheeks and chin are also yellowish white, as are two conspicuous spots just above the...

Biodiversity surveys

Biodiversity measures are based on the ability to accurately count the number of species within a given area and usually some measure of their relative or absolute abundance. Population management of both common and rare species relies on accurate measures of population numbers or at least a way to measure population trends. Most mammal populations or communities are too complex for every individual to be counted, therefore a sample is often taken of the population and the number is estimated...

Feeding ecology and diet

The diet is predominantly insects and other invertebrates such as earthworms, which the shrew opossums find by rummaging in the surface litter and investigating likely nooks and crannies along their regular runways. Like placental shrews, they hunt mainly by smell they also have sharp hearing, but their eyesight is relatively poor. Various species have also been reported feeding opportunistically on fruit, scavenging the flesh of dead animals, and killing and eating the young of other mammals...

Contents

How to use this Advisory Contributing Contributing Contributions of molecular genetics to 26 Sensory systems, including echolocation 79 Reproductive Nutritional Distribution and Cognition and Mammals and humans Domestication and Mammals and humans Mammalian invasives and Mammals and humans Field techniques for studying Mammals and humans Mammals in zoos 203 Family Family Duck-billed Order DIDELPHIMORPHIA New World opossums Family New World Order PAUCITUBERCULATA Shrew opossums Family Shrew...

Domestic donkey Equus africanus f asinus

It is said that the donkey is the horse of the poor people and undeservingly it remains in the shadow of its more famous relatives. It is not actually headstrong, dumb, and lazy. It has only a more evolved instinct of self-preservation, which allows it to preserve itself from human service. The donkey does not as a rule bond emotionally to humans as horses do. If it has good treatment and a warm stable, it is a priceless helper, especially in stony terrain. It does not mind hot weather or...

Conclusion

There are many more stories of invasive mammals to tell, and more details untold about feral pigs, foxes, rabbits, cats, squirrels, rats, mice, horses, burros, and other invasive mammals than can easily fit on the printed page. But this overview of mammalian invasions contains many of the basic principles needed to better comprehend the plethora of media stories on invasive mammals. Many of the invasive mammal examples have been from islands, as scientists prefer to study the simplest possible...

Evolution and systematics

The order Dasyuromorphia includes three families of carnivorous marsupials in the superfamily Dasyuroidea the Dasyuridae (dasyures), the Myrmecobiidae (numbat), and the Thylacinidae (thylacines). The dasyurids and thylacinids are more closely related to each other than they are to the num-bat. The Australian marsupial radiation produced a number of other species of carnivorous marsupials in the otherwise herbivorous order Diprotodontia. These include two genera (Thylacoleo and Wakaleo) and...

What is the breed

The basic category of domestic animals is the species, as is the case with wild animals. The species of domestic animals are differentiated into breeds, while that of wild animals are differentiated into subspecies. A breed is defined as a group of animals that has been selected by humans to possess a uniform appearance that is inheritable and distinguishes it from other groups of animals within the same species. Domestication and selective breeding have changed some species of domestic animals...

Threatened breeds

Enormous numbers of different breeds have developed during many millenia, most very well acclimatized to local conditions. It is estimated that 5,000-6,000 breeds exist today. Four thousand belong to the so-called big nine (cattle, horse, donkey, pig, sheep, goat, buffalo, domestic fowl, duck). However, the trend has moved to renewed selection efforts during the latest decades, for example, the present specialized daily milk production capacity of a Holstein Friesian averages 10.6 gal (40 l) of...

Sperm competition

Females by definition are the sex that produces larger gametes. Once they've deposited their smaller gametes, males are in the advantageous position to limit energetic input (e.g., leave). The females are then left with the decision to raise offspring or not, and this decision has important energetic implications. But males also have one evolutionary uncertainty to overcome the certainty of paternity. If males release millions of sperm and can father multiple...

Neighbors competitors and friends

Mammals and humans have been the closest relatives and nearest neighbors throughout the entire history of humankind. Mammals contribute essentially to our diet and we keep billions of domesticated mammals solely for that purpose. Hunting mammals for protein-rich meat became an essential background factor in human evolution several million years ago. More recently, the discovery of how to get such animal protein in another way started the Neolithic revolution some 10,000 years ago. The symbiotic...

Significance to humans

Numbat is an aboriginal name from South Australia. Central Australian aboriginal peoples knew the animal as Numbats (Myrmecobius fasciatus) use scent and a long sticky tongue to locate their prey. The tongue can extend as far as 4 in (10 cm) from its mouth. (Photo by Bill Bachman Photo Researchers, Inc. Reproduced by permission.) Two juvenile numbats (Myrmecobius fasciatus) in Western Australia. (Photo by Animals Animals A. Wells, OSF. Reproduced by permission.) walpurti and hunted it to eat....

Domestic yak Bos mutus f grunniens

The yak was domesticated in Tibet from 3000 to 1000 B.C., and its progenitor is the wild yak (Bos mutus). It is almost one This domesticated dog has been trained to help hunters retrieve game. (Photo by St. Meyers Okapia Photo Researchers, Inc. Reproduced by permission.) This domesticated dog has been trained to help hunters retrieve game. (Photo by St. Meyers Okapia Photo Researchers, Inc. Reproduced by permission.) third smaller than its wild progenitor and it has markedly weaker horns or no...

Mitochondrial DNA

Images Placental Mammals

The ring-shaped, double-stranded mtDNA molecule has the same basic structure in all mammals. It is approximately 16,500 bp in length and contains coding sequences for 13 genes, 2 ribosomal RNA molecules (12S and 16S), and 22 transfer RNA molecules, together with a non-coding control region (D-loop). In contrast to nuclear genes, there are no introns in mtDNA. Furthermore, mtDNA differs from nDNA in another crucial respect that simplifies analysis of its evolution. In mammals, mtDNA is...

Didelphimorphia New World opossums

Class Mammalia Order Didelphimorphia Family Didelphidae Number of families 1 Small- to medium-sized terrestrial mammal with long, naked tail, opposable thumbs both in the hands and feet, long, pointed snout, naked ears that range from small to large, and medium to large eyes color varies from nearly pure white to blackish some species are unicolored, whereas others have distinct light and dark blotches and bands 3-22 in (8-55 cm) 0.9 oz-11 lb (25-5,000 g) Dry and moist tropical forests,...

Water opossum

Can Testicular Atrophy Reversed

Latra minima (Zimmerman, 1780), Cayenne, French Guiana. OTHER COMMON NAMES French Opossum aquatique German Schwimmbeutler Spanish Tlacuache de agua, cuica de agua, yapok, zorro de agua, comadreja de agua. Length 10.6-15.7 in (27-40 cm) weight 21.2-28 oz (600-790 g). Dense and silky hair with four to five broad dark brown bands across the back joined along the dorsal spine. Venter is silvery white and tail is almost naked and scaly. The eyes are large and black, and the face has another dark...

Reproductive biology

Spotted Tail Quoll Life Cycle Images

Short life spans, leading in their extreme form to single breeding followed by death in the first year of life (semel-parity), are a defining feature of carnivorous marsupials. Among mammals, semelparity has arisen only in dasyurids and didelphids, in which groups it has evolved at least six times, including in medium-sized species over 2.2 lb (1 kg) in body weight (northern quoll, Dasyurus hallucatus). All carnivorous marsupials, including thylacines and possibly numbats, A spotted-tailed...

Peculiar mechanism Reproduction in armadillos

Armadillos are placental mammals (Order Xenarthra) that occupy the southern United States, Central America, and the northeastern half of South America. They differ from other placental mammals in numerous ways. The uterus is simplex, just like that of humans, but there is no vagina and instead, a urogenital sinus serves as vagina and urethra. Males have internal testes and no scrotum, and have among the longer penes of mammals, reaching one third the length of the body in nine-banded armadillos...

Bats own the night sky

Bats are extremely successful nocturnal mammal fliers. Their anatomy, physiology, and ecology are a finely tuned integration of many different body organs and organ systems that enable these animals to dominate the night sky. Bat adaptations for flight include more than just wings. The diet consists of high-calorie food that is easy to digest, assimilate, and pass quickly through the gut. They have solved thermoregu-latory problems ranging from the heat loss due to small size to the heat load...

Sheep Ovis ammon f aries

Sheep and goats are assumed to be the oldest domestic livestock. Sheep are bred in different areas around the world from lowlands to mountains and from tropics to cold north moorlands. They are exceptionally acclimatized to extreme conditions. They are also very useful, providing meat, milk, tallow, wool, fur, leather, horn, lanolin, dung, and they carry loads in Tibet. No culture or religion forbids killing sheep or eating sheep meat. The exact origin of the domestic sheep is not clear because...

Mulgara

Dasycercus cristicauda (Krefft, 1867), South Australia, Australia, probably Lake Alexandrina. Two subspecies described. OTHER COMMON NAMES English Crest-tailed marsupial mouse. Length 4.9-8.7 in (125-220 mm). Light brown above, pale below with crest of long black fur distal two-thirds of short tail short, rounded ears stores fat in the base of the tail. Inland central and western Australia. HABITAT Found in arid, sandy regions. BEHAVIOR Lives solitarily in burrows it digs in flats between or on...

Ethiopian region

This region includes Africa south of the Sahara, Madagascar, and the southwest corner of Arabia. Its mammal fauna exhibits the greatest diversity of all the major regions and 13 out of 26 orders are present. One of these is endemic, Tubu-lidentata, with a single species, the aardvark. There are 52 families (18 endemic), and over 1,000 species (more than 90 endemic). Endemic families include Giraffidae, Hippo-potamidae, Chrysochloridae (golden moles), Tenrecidae (ten-recs), and Macroscelididae...

Biased knowledge

Squirrel Medic

Still, general knowledge on the subject is rather incomplete and heavily biased in several aspects. Most of the arti cles have been authored and co-authored by very few persons or research teams. Thus, 31 (410 out of 1,300) of the scientific papers bear a signature of one or more of just five authors (Bennett, Burda, Heth, Jarvis, and Nevo), while the most influential of them, Eviatar Nevo, has authored or co-authored 225 of them. As a consequence since every scientist observes the world...

Indirect observations

Many behaviors can be indirectly inferred from sign indexes and density estimates. Habitat selection is often measured through indexes that compare an animal's use between habitats or seasons. When indexes are used as a surrogate for direct observations, the closer the index is to the target behavior the less chance of error. For example, a browse index based on the number of buds clipped per tree is directly re lated to ungulate feeding, while pellet or track counts are more indirect indexes....

Behavioral plasticity

Learning in itself, of course, is by no means specific for mammals, or even higher animals. When asking the first Tinbergen question, we then have to look for those areas of behavioral plasticity that distinguish mammals from their reptilian ancestors. So-called higher forms of learning, which require certain degrees of neural complexity, are (among others) spatial memory and cognitive mapping. Predators that follow prey, primate bands that follow certain routes between sleeping and foraging...

Information Of Mammals Foreword

No one knows exactly how many distinct organisms inhabit our planet, but more than 5 million different species of animals and plants could exist, ranging from microscopic algae and bacteria to gigantic elephants, redwood trees and blue whales. Yet, throughout this wonderful tapestry of living creatures, there runs a single thread Deoxyribonucleic acid or DNA. The existence of DNA, an elegant, twisted organic molecule that is the building block of all life, is perhaps...

Three ecological postulates that underlie conservation biology

Modern conservation biologists must often transcend the traditional boundaries of academic disciplines, for these scientists increasingly need to know about politics, economics, philosophy, anthropology, and sociology in order maintain or restore the health of ecosystems. However, because conservation biology is fundamentally concerned with the dynamics of wildlife populations, a solid understanding of biology and ecology is paramount for workers within the discipline. Three ecological...

Behavior

Australian mammals are almost all nocturnal or crepuscular and the carnivorous marsupials are no exception. Most are nocturnally active, although some diurnal foraging and basking activity has been recorded in a number of species for which detailed field observations are available, including in antech-inuses and thylacines. In some populations, spotted-tailed quolls exploit opportunities to prey upon nocturnal possum prey asleep in tree hollows, and are almost arhythmic in their activity. Three...

Captive breeding and reintroduction

In recent years ex situ conservation efforts have become increasingly important. Zoos, botanical gardens, wildlife parks, and conservation trusts now work in collaboration to maintain captive assurance colonies of threatened plants and animals. Studbooks on target species are kept by participating institutions, and breedings are scheduled in consultation with conservation geneticists. The proximate mission of ex situ colonies is to maximize genetic diversity within a captive population of...

Reproduction in marsupials

In marsupials, ova are shed by both ovaries into a double-horned or bicornate uterus. The developing embryos remain in the uterus for 12-28 days, and most of the nourishment comes from an energy sac attached to the egg (yolk sac). There is no placenta (except for one groups of marsupials, the bandicoots, that have an interchange surface that resembles a true placenta). Gestation is thus short (less than one month), and much of the development of the young will occur outside of the female...

Physical characteristics

Dasyuromorphians are quadrupedal (move on four legs), with four toes on the front feet, four or five toes (including The Tasmanian devil (Sarcophilus laniarius) has teeth capable of crushing bone. (Photo by Erwin & Peggy Bauer. Bruce Coleman, Inc. Reproduced by permission.) The Tasmanian devil (Sarcophilus laniarius) has teeth capable of crushing bone. (Photo by Erwin & Peggy Bauer. Bruce Coleman, Inc. Reproduced by permission.) a clawless toe called a hallux) on the hind feet, long tails...

How to get through

The most significant challenge is a mechanical one soil is a dense, more or less hard and compact medium that cannot be penetrated easily. Movement through soil is energetically very costly. Vleck (1979) has estimated that a 5.3-oz (150-g) pocket gopher burrowing 3.3 ft (1 m) may expend 300-3,400 times more energy than moving the same distance on the surface. To keep the energy costs of burrowing at the minimum, the tunnel should have a diameter as small as possible. To achieve this,...

Cardiovascular and respiratory adaptations

Like birds, bats have hearts that are about three times bigger than those of comparably sized mammals. The heart muscle fibers (or cells) in bats possess higher concentrations of ATP (the molecule that is utilized for energy by cells) than observed in any other mammal. These adaptations enables bats to pump more blood during a flight, a period of peak demand for oxygen. Resting bats may have heart rates as low as 20 beats per minute. Within minutes of initiating flight, the heart rate may rise...

Sperm and egg formation

Sperm cells are made in the testes of males. Through a process of cellular division called meiosis, sperm-producing cells with regular genetic material (diploid cells, meaning they posses two copies of each chromosome) undergo division with the end product being two cells each with only one copy of each chromosome (haploid, half of the parent cell). Because sperm production is optimal at temperatures slightly colder than average body temperature, testes are housed in a pouch These giraffes...

Challenges

Because water is so dense (up to 800 times denser than air), it can easily support an animal's body, eliminating the need for weight-bearing skeletons like terrestrial animals. Water is also more viscous than air, and this coupled with the high density has resulted in aquatic animals adapting a very streamlined shape, particularly the carnivores. This makes them very fast and powerful swimmers, enabling them to catch their prey. Many of the adaptations of aquatic organisms have to do with...

Longtailed planigale

Planigale ingrami (Thomas, 1906), Alexandria, Northern Territory, Australia. Length 2.2-2.6 in (55-65 mm). Smallest of the planigales and the smallest marsupial with very flat head and thin tail longer than head and body. Seasonally flooded grasslands and savanna woodlands. Forages and rests in crevices in moist, contracting (cracking) soils, under rocks, and in tussocks. Planigales may have evolved the very flat head to occupy the niche of foraging in seasonally flooded cracking soils....

How to tell time

Light-dark rhythm (photoperiod) is known to regulate production of the hormone melatonin that, in turn, regulates circadian (meaning around a day, as in a 24-hour period) rhythms by a feedback mechanism. In surface-dwelling vertebrates (including human), melatonin is produced during dark hours. It can therefore be expected that subterranean mammals living in constant darkness would display high melatonin levels. This does seem to be the case, yet the role of melatonin in regulating activity...

Nutrition and the reproductive cycle

Energy requirements and food intake of pregnant females are about 17-32 higher than non-reproducing females, and yet only 10-20 of this additional energy is retained as new tissue by the developing uterus. The rest of the energy is lost as heat, slowing down the growth rate and thus lengthening the gestation period. A slower fetal growth rate may be advantageous in an environment with limited dietary protein or minerals, especially in the case of such animals as the fruit-eating or leaf-eating...

Gestation and neonate type

Period Gestation

With only a few exceptions, each mammal species has a characteristic gestation period that shows remarkably little variation. In comparisons between species, gestation periods tend to increase as body size increases. However, effective comparisons of gestation periods among mammals must take into account a fundamental distinction in the state of the neonate at birth. As a general rule, it is possible to distinguish fairly clearly between mammals that give birth to several poorly developed...

Alstons woolly mouse opossum

Allen, 1900 , Cartago, Costa Rica. OTHER COMMON NAMES French Souris-opossum laineuse d'Alston Spanish Zorrici. PHYSICAL CHARACTERISTICS Length 6.7-7.9 in 17-20 cm weight 2-5.3 oz 60-150 g . One of the largest mouse opossums. The dorsal hair is yellowish brown to reddish underparts are paler. Distinct black mask over each eye. The tail is long, slender, and naked. There is no marsupium. The feet have strongly opposable thumbs. Caribbean coast of Central America from...

Humans the most successful invasive species

The magnitude of the invasive species problem in agricultural and natural ecosystems prompted U. S. President Bill Clinton to organize the heads of eight federal agencies into the National Invasive Species Council in 1999. Actually, humans rank among the most successful invasive mammal species. Humans are believed to have spread from Africa to Europe and Asia over 100,000 years ago, and reached the island continent of Australia between 40,000 and 60,000 years ago. But humans are apparently...

Milk and lactation

Platypus Egg Yolk

At birth, the young no longer can rely on the direct exchange of nutrients through the placenta or in monotremes, through nutrient stored in the egg . Thus, nutrition of young requires an additional process, and milk is the nutrient that serves that purpose. Milk is unique to mammals, and all species of mammals are capable of producing milk. Milk production occurs in the mammary glands, which resemble sweat glands in form but become mature only following parturition or birth of young. The milk...

Nearctic

This region comprises North America up to northern Mexico and Greenland. Ten orders are present, including 37 families, and around 643 species. Two families are endemic, each containing a single species. These are the Antilocapri-dae pronghorn and the Aplodontidae sewellel, or mountain beaver , endemic to western North America. There are a large number of endemic rodents. These include the woodrats genus Neotoma , 17 species of ground squirrel Citettus , three antelope squirrels, 16 chipmunks,...

Peculiar processes Delayed fertilization and delayed implantation

Barred Bandicoot Nest

The opportunity to find a suitable mate is essential for reproduction, but because gestation is fixed in duration, timing of mating has direct implications on the timing of parturition. However, mammals have evolved two strategies to separate A western barred bandicoot Perameles bougainville joey suckling in mother's pouch. Photo by Jiri Lochman Lochman Transparencies. Reproduced by permission. A western barred bandicoot Perameles bougainville joey suckling in mother's pouch. Photo by Jiri...

Reproductive system

There are three different modes of reproduction used by mammals. The monotremes, whose extant members are the echidnas and duck-billed platypuses, lay eggs. The therians marsupial and placental mammals give birth to live young. Marsupial newborns are undeveloped some mammalogists call them embryos . After only a short gestation period they must make their way to a teat outside the mother's body a teat that may be in a pouch in species that have pouches to finish development. The embryos of...

Social systems

Sexual reproduction in animals generally puts a heavier load on the female side. In mammals, however, this bias in cost of reproduction is far more extensive due to the period of gravidity pregnancy and the subsequent lactational period, both of which cannot be taken over by a male. Consider a female mouse suckling six young shortly before weaning, each young has about half her weight. Thus, she has to nourish and support 400 of her body weight There is an even higher evolutionary pressure on...

How to find a partner

In order to reproduce, mammals have to find and recognize an appropriate mate belonging to the same species, opposite sex, adult, in breeding mood, sexually appealing . Monogamous mammals undergo this search once in life solitary mammals have to seek mates each year. Subterranean mammals do not differ in this respect from their surface-dwelling counterparts. In 1987, two research teams reported, simultaneously and independently, the discovery of a new, previously unconsidered, mode of...

Camels and llamas

The camel was and is an excellent transport vehicle in desert areas where horses and donkeys cannot survive. In deserts, camels can survive ten times longer than humans and four times longer than donkeys. They provide meat, milk, blood, leather, and hair, and excrements are used as fuel. The wild Bactrian camel Camelus ferus is the ancestor of the Bac-trian or two-humped camel C. ferus f. bactrianus . It comes from east and central Asia. The remaining populations live in the periphery of the...

Body design

To understand bat body adaptations for flight, it may be instructive to examine bird bodies. Bird bodies are designed for mass reduction. They do this in a number of ways. They have lost teeth and the accompanying heavy jaws and jaw musculature over evolutionary time. They have thin, hollow, and strong bones. Many bones are fused or reduced in size. The long bony tail of their ancestors has been greatly reduced to the small vestigial pygostyle. Birds have a series of air sacs in the body that...

Sexual dimorphism

Male and female mammals obviously differ in various features that are directly linked to reproduction, as is the case with the sex organs of both sexes and the mammary glands of females primary sexual characteristics . However, males and females can also differ in a variety of features that are not directly associated with reproduction secondary sexual characteristics . Such secondary differences between males and females, like the human facial beard, are collectively labeled sexual dimorphism....

Migration

Caribou Migration

Migrations are mass movements from an unfavorable to a favorable locality and in plains-dwelling, large herbivores such as reindeer, bison, zebras, wildebeest, or elk they can be quite spectacular. In large sea mammals migrations are no less important, but to us are merely less visible and it has taken much effort by science to document at least a part of their extent, leaving much that is still shrouded in mystery. Mass-migrations occur when individuals flood to distant birthing or breeding...

Delayed fertilization

Sperm storage occurs in bats inhabiting northern temperate regions such as the little brown bat Myotis lucifugus , and also in many bats such as noctule Nyctalus noctula . In the little brown bat, the testes become scrotal in the spring, and most sperm production is completed by September. The sperm are then stored until copulation commences months later. Females are inseminated in the fall and winter, while they are in hibernation. Sperm are then stored again, this time in the female...

The Hagenbeck concept

Carl Hagenbeck was an animal entrepreneur. He supplied animals to zoos and was also an animal trainer. He pioneered many display and exhibit techniques. Hagenbeck initially gained his reputation by exhibiting people and animals in traveling exhibits. On October 6, 1878 over 62,000 people visited the Berlin Zoo to see his traveling exhibit of Nubians from the Sudan, Laplanders, Eskimos, Kalmucks, Tierra del Fuego natives, and Buddhist priests. There were also elephants, camels, giraffes, and...

Oriental region

The Oriental region includes Asia south of the Himalayas, southern China, the Philippines, and Southeast Asia up to Wallace's Line, between the islands of Bali and Lombok. The region has two endemic orders, Scandentia tree shrews , with 19 species, and Dermoptera colugos . There are two species of colugos, often also called flying lemurs, a doubly confusing name as they are not lemurs and they glide, rather than fly. There are 50 families in the region, four endemic, and 260 genera, about 35 of...

Sexual selection and the evolution of species and their attributes

The pressures caused by females choosing males will lead to two types of evolutionary selection inter-sexual selection adaptations to win members of the other sex , and intrasexual selection adaptations to win access to mates over members of the same sex . Both vary in importance according to species and environments. Inter-sexual selection leads to the development of adaptations, morphological, physiological, or behavioral, to seduce Top Placental mammal development. Middle row Marsupial...

Domestic horse Equus caballus f caballus

Image Farmer Plowing With Draft Horse

The horse was the last of the five most common livestock animals to be domesticated. After a short period when it was used only as a source of meat, it became established as a perfect means of transport until the recent past. The history of the wild horse in Europe and Asia from the end of the Pleistocene until its domestication in perhaps 4000 to 3000 B.C. is poorly understood. According to prevailing opinion, wild horses during the domestication belonged to two species. These were the...

Bali cattle Bos javanicus f domestica

Bali cattle is the domestic form of wild banteng B. javanicus , which lives in the forests of Java, Borneo, Malaysia, and Thailand today. Its domestication took place in Java around 1000 B.C. Wild bantengs were caught and tamed in the Middle Ages, in Bali, Sumatra, and Java until the eighteenth century. Bali cattle are smaller than banteng, the horns lack the characteristic curvature, and the skull is smaller. The external sexual signs are weaker than in the wild species. The domestic species...

Density estimate

Density estimates have two components, and both cause difficulties to biologists the amount of area surveyed and the number of animals. As opposed to an index, the density estimate relies on a measure of area surveyed and not on effort. If the survey area is a true island, then the measurement is straightforward. If the survey area has an arbitrary boundary between inside and outside, assumptions have to be made as to how the animals move with respect to the boundary. If the area surveyed is a...

Horns and antlers

Horns and antlers are found in the order Artiodactyla cattle, sheep, deer, giraffes, and their relatives . Several other types of mammals have similar head structures, but true horns, originating from the frontal bone of the skull and found only among the Bovidae cattle, antelopes, buffalo , consist of a bony core enclosed by a tough keratinized epidermal covering or sheath. True horns are not branched, although they may be curved. Horns grow throughout the life of the animal and are used for...

Gayal Bos gaurus f frontalis

The gayal or mithan is the domesticated form of the wild gaur B. gaurus . For a long time, it was not clear if the gayal and gaur were the same separated species or if the gayal had developed by crossbreeding of a gaur with bantengs or zebu. The gayal is noticeably smaller than the gaur, it has shorter conical horns, a markedly shorter skull, and a wider and flatter forehead. It has a large double dewlap on the chin and neck. It is most commonly brown and black but can also be spotted or white....

Adaptations in the digestive system

Digestive System Mammal

All carnivores, when fed a whole prey-based diet, consume proteins and fats from the muscle, vitamins from organs and gut contents, minerals from bones, and roughage from the hide, feathers, hooves, teeth, and gut contents. Felids are set apart from other, more omnivorous meat eaters because of their inability to effectively utilize carbohydrates as an energy source. They therefore depend on a higher concentration of fats and protein in their diet, as well as dietary sources of preformed...

Record keeping

Animal record keeping is the foundation of captive animal management. Zoo professionals depend on detailed direction from animal records. Mammals with missing or unknown ancestry or other life history information are of very limited use in long term management strategies. The International Species Information System ISIS , first developed in 1973, collects animal data from over 560 institutions in 72 countries on 6 continents and stores them in a computerized database. These data are kept by a...

Mammals IV

Abercrombie, PhD Wofford College Spartanburg, South Carolina Cleber J. R. Alho, PhD Departamento de Ecologia retired Universidade de Bras lia Bras lia, Brazil Universidad de la Rep blica Oriental Anders Angerbj rn, PhD Department of Zoology Stockholm University Stockholm, Sweden William Arthur Atkins Atkins Research and Consulting Normal, Illinois Paul J. J. Bates, PhD Harrison Institute Sevenoaks, Kent United Kingdom Amy-Jane Beer, PhD Origin Natural Science York, United Kingdom...

Bat wing morphology and its role in powered flight

Chief among the many adaptations of the bat for powered flight is the bat wing, and the flapping flight style that uses muscle power to generate lift and thrust. The bat wing evolved from the forelimbs of a terrestrial mammalian ancestor. The mammalian forelimb is exceedingly mobile because the shoulder joint between the scapula shoulder bone and the humerus upper forelimb bone is loosely held together with muscles. This allows for actual rotation of the arm around the shoulder joint in many...

The physics of powered flight

Glaucomys Volans

Once a means for detecting and avoiding obstacles was developed in a bat ancestor, the lineage was free to expand into the nocturnal flier niche. Powered flight allows access to flying insects. Because gliders do not have the maneuverability to pursue flying insects, this feeding niche was wide open during early bat evolution. The difference between powered flight and other modes of traveling through the air is maneuverability. Gliders such as the colugo have extra skin at the body's sides,...

What is rumination

The act of rumination, or chewing the cud, is the regurgitation and remastication of undigested fibrous material before it is swallowed again. As the food reenters the rumen, it undergoes further fermentation. The products of fermentation in the form of broken-down food particles then slowly pass to the other parts of the stomach, where the usual digestive juices of the abomasum perform their work. Ruminants secrete copious amounts of saliva that serve to buffer fermentation products in the...

The diversity of mammalian social systems

Microgale Longicaudata

Before approaching explanatory questions by means of Tin-bergen's questions again, a brief attempt at categorization of social systems in order to categorize the diversity of mammalian social systems, there are several variables that need to be described for each species. One is the degree of sociality. We find at least three types of social organization here first are the solitary individuals that do not regularly have any social contact with conspecifics outside the narrow timespan of...

Body design and skeletal system

Mammal Reptile Ear

As endotherms, mammals require more energy than ec-tothermic animals. Consequently, many mammal traits evolved to conserve energy. This is particularly true of the mammal skeleton. Mammals differ as a group from other living quadrupedal vertebrates in that their limbs are positioned directly below the body, allowing more energy-efficient locomotion. The lateral placement of the limbs on reptiles and amphibians requires them to spend considerable energy keeping their bodies lifted off of the...

Reproductive processes

Mammal Reproduction

The primary reproductive process in female mammals is the production of eggs ova from follicles in the ovary. In a non-pregnant female mammal, production of eggs is typically a cyclical process, although there are varying degrees of seasonal restriction such that some female mammals do not show repeated cycles. Seasonality of reproduction in mammals is mainly governed by annual variation in rainfall and vegetation, and hence becomes increasingly common at high latitudes. In many mammals,...

Sociality in the framework of Tinbergens questions

What do we know about phylogeny It is not normally possible to find behavior in fossilized form, thus we have to take another, but also reliable approach, by comparing the phenomenon in question among as many living species as possible. When doing this with regard to social systems, the most basic one seems to be a sort of solitary or dispersed female system, foraging alone in undefended home ranges. This pat tern can be found in members of so many different taxa that we may assume it to be one...

A zoologist answers A highly derived amniote

Black Handed Spider Monkey

Many of the characters common to mammals do not appear in other animals. Some of them, of course, can be observed also in birds a very high in respect to both maximum and mean values metabolic rate and activity level or complexity of particular adaptations such as advanced parental care and social life, increased sensory capacities, and new pathways of processing sensory information or enormous ecological versatility. Fine differences between birds and mammals suggest that the respective...

Role of sensory data

Bing Wallpaper Gallery

Mammals sense or gather information about their environment and use it to make decisions that affect their survival and reproduction. Sometimes, species initially respond to one type of cue. For example, female hammer-headed bats Hypsig-nathus monstrosus in Africa locate groups of males by listening to their distinctive calls. Picking a male to mate with, however, is a decision females appear to make only after visiting several in the line of displaying suitors. A female's actual choice may...

The dietary needs of mammals

Like the rest of the animal kingdom, mammals need food for energy and the maintenance of bodily processes such as growth and reproduction. The chemical compounds used to supply the energy and building materials are obtained by eating plants or organic material. Both plant- and animal-based sources of food are made up of highly complex compounds that need to be digested and broken down into simpler forms. Four of the most common naturally occurring elements oxygen, carbon, hydrogen, and nitrogen...

Nervous system and sensory organs

Convolutions The Neo Cortex

Mammals have relatively larger brains than other vertebrates. From monotremes to marsupials to eutherians, the mammal brain increases in size and complexity, primarily by the expansion of the neopallium. The neopallium or neo-cortex is a mantle of gray matter that first appeared as a small region between the olfactory bulb and the larger archipallium. The neopallium in mammals has expanded over the primitive parts of the vertebrate brain, dominating it as the cerebral cortex. The cerebral...

Cardiovascular and respiratory systems

Oxycyznated Red Blood Cells

In order to distribute nutrients and oxygen needed for metabolism, mammals need a highly efficient circulatory system. The main differences in circulatory structure between mammals and most other vertebrates are in the heart and in the red blood cells. The mammalian heart has four chambers as do birds and crocodilian reptiles compared to the three chambers found in the reptiles except the crocodilians . The additional chamber is the result of a muscular wall or septum that divides the ventricle...