Feeding ecology and diet

Elapids are diverse in both diet and method of obtaining food. These snakes use envenomation rather than constriction to subdue prey. The chief prey are small vertebrates (rats, mice, birds, snakes, lizards, frogs, and fishes) and sometimes eggs. Some snakes specialize. The southern African Rinkhal's cobra (Hemachatus haemachatus) has a special fondness for toads.

In Australia, only death adders (genus Acanthophis), brown snakes (genus Pseudonaja), black snakes (genus Pseudechis), and taipans (genus Oxyuranus) eat small mammals as a large part of the diet, but they also eat other prey. Many of Australia's diverse terrestrial elapid fauna specialize on small reptiles, mostly scincid lizards, which the snakes find by searching under cover or by active foraging. Other elapids specialize on frogs, which they find at water's edge or under cover.

Both the partially marine sea kraits (Laticauda) and the diverse fully marine seasnakes obtain all their food from the aquatic habitat. Sea kraits specialize on eels they find among the reefs. Seasnakes have diverse diets. Most eat relatively sedentary fish that are easy to catch, but they tend to specialize on one or a few fish shapes, ranging from short gobies to long eels to squid. Three species of seasnake eat only the egg masses of fishes.

Homorselaps Lacteus Spotted Form
A spotted harlequin snake (Homoroselaps lacteus), a very primitive elapid, eating its main diet, black threadsnakes (Leptotyphlops nigricans). (Photo by Bill Branch. Reproduced by permission.)
A sea krait (Laticauda colubrina). (Photo by A. Power. Bruce Coleman, Inc. Reproduced by permission.)

King cobras eat other snakes, including venomous species. Australian bandy-bandy snakes (genus Vermicetta) eat nothing but blindsnakes. Many coral snakes specialize on other snakes. Some species of Australian sand-swimming snakes of the genus Simoselaps eat nothing but the eggs of other reptiles. They ingest the small eggs whole and then, it is thought, regurgitate the empty shells.

Most elapids are active foragers. The Australian death adder (genus Acanthophis), however, stays in position and undulates the tip of its tail (which in contrast to the rest of the tail is yellowish white, resembling a larval insect) to lure prey. Australian whipsnakes (genus Demansia) have large eyes and are very active and visual daytime hunters. African mambas (genus Dendroaspis) also have large eyes to help them locate small mammals.

There is dispute about how many times live-bearing has evolved in the Australian elapid radiation. It is known that live-bearing has evolved at least twice independently, once in the main live-bearing radiation and once in the red-bellied black snake (Pseudechis porphyriacus). The other members of this genus are egg layers. The fully marine seasnakes also are live-bearers.

Most elapids do not take care of their eggs or young. In egg-laying species, females find suitable spots to lay eggs— under a rock, in or under a log, or in a crevice—and vacate the site. The eggs incubate for approximately three months, and the young hatch and are immediately on their own. In live-bearing species, the mother goes through a three-month pregnancy and gives birth in a secluded spot. Like the hatch-lings, the liveborn young are immediately on their own. An exception is king cobras, which form a pair bond and build a nest from leaves and soil. King cobra pairs protect their nests and their eggs and can be very aggressive during breeding season.

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