In evolutionary biology, mimicry in vertebrates is mimicry by a vertebrate of some model (an animal, not necessarily a vertebrate), deceiving some other animal, the dupe. Mimicry differs from camouflage as it is meant to be seen, while animals use camouflage to remain hidden. Visual, olfactory, auditory, biochemical, and behavioral modalities of mimicry have been documented in vertebrates. There are few well-studied examples of mimicry in vertebrates. Still, many of the basic types of mimicry apply to vertebrates, especially among snakes. Batesian mimicry is rare among vertebrates but found in some reptiles (particularly snakes) and amphibians. Müllerian mimicry is found in some snakes, birds, amphibians, and fish. Aggressive mimicry is known in some vertebrate predators and parasites, while certain forms of sexual mimicry are distinctly more complex than in invertebrates.
Classification
Defensive
Batesian Batesian mimicry is a form of defense that allows a harmless species to mimic the appearance of a toxic, noxious, or harmful species to protect itself from predators. By mimicking the appearance of a harmful species, a predator is less likely to attack the species due to its awareness of the signal of warning color patterns. Batesian mimicry occurs in multiple vertebrates, but is less prevalent in mammals due to a relative rarity of well-marked harmful models. However, this form of mimicry is prevalent in snakes and frogs, where chemical defense has coevolved with distinct coloration. Still, mammals have evolved Batesian mimicry systems where particularly powerful or harmful models exist.
For example, Batesian mimicry may occur in cheetah cubs. They replicate the appearance of a sympatric species, the honey badger (Mellivora capensis). The honey badger has a white or silvery back with a black or brownish underbelly and grows to a body length of about three feet long and ten inches high. As cubs, cheetahs have the same reverse-countershading color pattern and are roughly the same size. Due to this conspicuous coloration, potential predators like lions and birds of prey are less likely to hunt cheetah cubs, as from a distance they appear to be honey badgers. Honey badgers make an effective model because their aggressive nature and glands on their tails that produce a noxious fluid enable them to deter predators up to 10x their size. Batesian mimicry also occurs in the scarlet kingsnake. This species resembles the venomous coral snake, sharing a pattern of red, black, and yellow bands. Although the order of the color rings differ between the two snakes, from a distance a predator can easily mistake the scarlet kingsnake for its venomous model.
Müllerian Müllerian mimicry is another form of defensive mimicry, except the system involves two or more species that are all toxic, noxious, or harmful. These species develop similar appearances to collectively protect against predators. This adaptation is said to have evolved due to the additive protection of many species that look the same and reliably have harmful defenses. That is to say, this mimicry system evolves convergently. If a predator is aware of the potential threat of one species, the predator will also avoid any species with a similar appearance, creating the Müllerian mimicry affect. Again, the relative lack of noxious models limits most examples to systems that involve reptiles or amphibians. Müllerian mimicry is found in many pitvipers. All pit vipers are capable of delivering a life-threateningly venomous bite. In Asia, different species found throughout Asia have evolved separately to have a very similar appearance. Each species is found in different places in Asia, but have the same green coloration with reddish tail tip. These shared colorations are warnings signals for predators. Because a predator is aware of these warning signals, it will avoid all species with this color pattern. Species that benefit from this system include Trimeresurus macrops, T. purpureomaculatus, Trimeresurus septentrionalis, T. flavomaculatus and T. hageni. Müllerian mimicry is also found in a ring of poisonous frog species in Peru. The mimic poison frog (Dendrobates imitator) mimics 3 similarly poisonous frogs of the same genus that live in different areas. These are D. variabilis, D. fantasticus, and D. ventrimaculatus. D. imitator can replicate the different appearances of all 3 species with color patterns ranging from black spots with yellow back and bluish green limbs, larger black spots with yellow outline, and black linear spots with yellow and bluish green outline.
The slow loris is one of the few known venomous mammals, and appears to use Müllerian mimicry for protection. It is hypothesized that this venom may have allowed it to develop a system of Müllerian mimicry with the Indian cobra. Slow lorises appear to look similar to the cobras with "facial markings undeniably akin to the eyespots and accompanying stripes of the spectacled cobra". Dark contrasting dorsal stripes are also apparent in both species, helping to confuse predators from above. When in aggressive encounters, slow lorises will make a grunting noise that mimics the hiss of a cobra. This example of Müllerian mimicry is likely unique to vertebrates due to its multiple modalities: biochemical, behavioral, visual, and auditory. Since the cobra is undoubtedly more dangerous to predators (and prey, as the loris eats predominantly fruits, gums, and insects), it is unclear if the benefit from this system is mutual; Still, both species are dangerous in their own right, and can therefore most accurately be classified as Müllerian.
Aggressive Aggressive mimicry is a form of mimicry, opposite in principle to defensive mimicry, that occurs in certain predators, parasites or parasitoids. These organisms benefit by sharing some of the characteristics of a harmless species in order to deceive their prey or host. Most examples of aggressive mimicry involve the predator employing a signal to lure its prey towards it under the promise of food, sex, or other rewards—much like the idiom of a wolf in sheep's clothing.
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