Snakes

Was this the snake that took a liking to John's arm last month? The answer has to be, No! For the second time since our arrival here in June, we had an encounter with a False Coral on Saturday. Sitting on a bank, watching us as we dug out weeds! It proved a real problem to identify but now we think that it must be a Tropical King snake Lampopeltis triangulum micropholis. These can grow to well over a metre and a half, though this one was just half a metre in length. The mostly non-venomous False Corals can almost all be identified by their body striping - black -> white -> black -> white -> orange (or yellow or other shades). The difficulty with identifying our 'catch' was that the markings were not cylindrical, but were patchy. The head gave us the real clue - big black and white scales, rather than the smaller head scales of other False Corals, and lacking the one single, orange head scale of the more likely Aesculapian False Coral. (Guia de Campo de Reptiles del Ecuador)

Mullerian mimicry in coral snakes and similar forms.

(Left) the venomous Eastern coral snake Micrurus fulvius; (right) the harmless king snake Lampropeltis polyzone; and (bottom) the moderately venomous rear-fanged false coral snake (Oxyrhopus). (These are not Ecuadorian species. This is a page from the on-line Encyclopedia Britannica.)

Ecuador has at least 12 species of False Coral, which apparently are Mullerian mimics of the venomous and quite frightening, but little studied, Coral snakes. The discussion about mimicry is a fascinating study, and was part of John's special investigations in Tanzania and later at the University of York. Those studies were of the East African Proteles cristatus or Aardwolf - a small, ant-eating and generaly harmless hyaena - which may mimic the larger and more fearsome Striped Hyaena Hyaena hyaena. In the case of False Corals, many biologists argue that their colouration is simply a product of convergent evolution, their stripes giving them and other species of snakes good camouflage. Does a snake predator have to first be bitten by a real Coral snake, and survive its encounter, to learn to avoid the mimics? One would think not! There is now a good body of research that suggests that snake predators are born with an instinctive avoidance behaviour of Corals and False Corals. This of course implies an evolved mimicry.