Reproductive biology

Female honey possums are larger than males and socially dominant. They can come into breeding condition at any time of the year, providing food is plentiful, though there is often a lull during mid-summer when nectar and pollen are less abundant. Males gather around an estrous female and com-

The honey possum (Tarsipes rostratus) has a dark stripe along its back to the end of its tail. (Photo by Dick Whitford/Nature Focus, Australian Museum. Reproduced by permission.)
A honey possum (Tarsipes rostratus) feeding on a Banksia flower. (Photo by © Jiri Lochman/Lochman Transparencies. Reproduced by permission.)

pete for the right to mate, before moving quickly on. Amazingly for such small animals, the sperm produced by males are very large—at 0.01 in (0.3 mm), they are the longest of any mammal. As if to redress the balance, female honey pos-

sums give birth to the smallest mammalian babies, each one weighing no more than 0.002 oz (5 mg). Most females will mate again almost immediately after giving birth. This second litter is an insurance policy—the fertilized eggs do not develop beyond a very early stage until the previous litter has left the pouch or died. Hence, while honey possum gestation requires only 3 weeks, pregnancies can last anywhere up to 13 weeks. Litters never contain more than four young; this is the maximum number a female can suckle on the four teats in her pouch. The litter spends about eight weeks in the pouch, during which time each baby grows to about 0.1 oz (2.5 g), which is a remarkable 500 times its birth weight. After that, the young are too big to fit in the pouch and the female deposits them in a spherical woven nest until they are weaned at about 10 weeks of age. A healthy female will normally rear two litters in a year, but will rarely live long enough to breed a third time.

Was this article helpful?

0 0

Post a comment