were there ever cobra in North America?
the hognose snake is a good example of a species that has evolved Batesian Mimicry, with their color and pattern being quite similar to some rattle snakes. it also has evolved the defensive maneuver of cobra, frilling their jaw and nexk out poised up. the looking like rattlers makes sense, but what Batesian Mimicry is the neck flare for? what is it trying to look like, if there are no cobra in North America..?
- Anonymous1 month ago
Similarity is not necessarily the result of mimicry. For example, the emerald tree boa and green tree python are very similar in color pattern, and yet they are almost certainly not mimics of one another since neither is venomous. Their color pattern is simply an adaptation to their similar environments. Rattlesnake colors are also an adaptation. They are cryptic in their environment. I remember driving on a road on Mt. San Jacinto and seeing a black colored rattlesnake. I cannot fathom why black color can be warning color for a snake. OTOH, dark color would help a snake warm up more quickly on the high altitudes of a mountain top. I also remember seeing a rattlensnake that has a color pattern similar to the banded phase of a California kingsnake at the edge of a grassy area. I also remember letting a California kingsnake go free on a grassy area, and watching it disappear after a few crawls. The color pattern of a kingsnake is simply good camouflage in their habitat of grasslands, with alternative dark and light patches of ground. The rattlesnake that I saw probably evolved to look similar to a kingsnake because it is good camouflage in the grassy area that it lives.
Some people believe that gopher snakes mimic the rattlensnake in color pattern, but that simply ignores the fact that rattlesnakes are cryptic and they do not use warning coloration to defend themselves. In fact, they evolved the rattle to warn animals like horses (which existed in North America before the end of the last ice age) and bison from stepping on them because they are not that easy to see even if they are out in the open. Why not evolve bright warning colors instead of a rattle? A more likely explanation is that gopher snakes, hognoses and rattlesnakes evolved similar color patterns because they live in similar environments, not because of mimicry of a dangerous species. IOW there is no value in looking like a rattlesnake. Instead it is only advantageous to a snake if its color pattern makes it hard to see in its environment.
Cobras never existed in North America, but their relatives, the coral snake, does. Elapid snakes apparently evolved in the Southern Hemisphere, judging from their distribution in Africa and South America as well as Australia. South America was once connected to Africa and Australia was connected to South America via Antarctica (before it was frozen solid). Cobras spread their hood to make themselves look bigger. Hognoses are small snakes, and they do not benefit much from looking big since that won't make them more frightening to potential predators. The eye spots on the back of a cobra make them look like the eyes of a big animal. It is a strategy often seen in fishes, caterpillars and even butterflies. The eyespots mimic the eyes of a big animal. Even the peacock uses eyespots of its tail feathers to try to scare away predators. In fact, real studies show that female peacocks are more likely to be eaten by predators than males, even though scientists think that male peacocks are more vulnerbale. Facts often contradict what some people assume. Many people assume that the black red and yellow color of coral snakes is warning coloration when in fact real studies show that coral snakes and the similarly colored mountain kingsnakes are very difficult to see in their natural environments. Studies show that birds will prey on coral snakes despite their supposed "aposematic coloration." Lastly, where a snake can benefit from having warning coloration, on the desert terrain of South Todos Santos Island, the mountain kingsnakes there have evolved to lose their red color and they look just like the California kingsnake. That example shows that being cryptic is better than being aposematic.
As some scientists point out, a tricolored snake may look conspicuous in an empty glass cage inside a laboratory, but not necessary in their native environment. One should not assume that a red, white and black colored snake is conspicuous in its own environment of black shadow, white sunlight and fallen red leaves. When scientists actually go out into the field to look for mountain kingsnakes, they find that they are actually well camouflaged in their woodland and forest environments. The California kingsnake is not a mimic of the banded krait either, since the venomous banded krait never existed in the New World. Both are similar in color because they are cryptic in their respective environments. Snakes prefer to be cryptic. The most gaudily colored snakes are actually cryptic in their native environments in all likelihood.
- The MikelLv 71 month ago
Nope, not naturally, but it is likely someone will smuggle one in and eventually it will be released or escape.