Other Batesian Mimics
Batesian mimicry is common among insects. It is also common
in many other invertebrates.
Some of the most remarkable mimics in this group are nudibranchs.
A nudibranch is a kind of sea slug. Nudibranchs eat algae,
anemones, coral polyps, and sponges. Some species also eat other
nudibranchs. Their colorful meals provide much of their own
color. This helps some species blend in with their surroundings.
Many nudibranchs store the venomous stings or bad-tasting
poisons of their prey and use them in their own defense. Predators
learn that the colors of these nudibranchs are warning colors. They
learn to leave them alone. Other nudibranchs mimic the colors of
the dangerous nudibranchs, and so do ocean-dwelling flatworms.
Batesian mimicry also appears in vertebrates. It is particularly
widespread in fish. The common sole, for example, is a European
fish with a fin on its back that is edged in black. It mimics
the weeverfish, which has venomous black spines in its back fin.
Both fish are well camouflaged by color and shape as they hide
in mud and sand underwater but raise their black-edged fins as a
warning when disturbed. Poisonous flatworms and venomous sea
urchins and sea snakes are also mimicked by fish.
One of the most remarkable fish mimics is a harmless species
called the comet, which lives on coral reefs of the Indian
Ocean and western Pacific Ocean. The comet is black with white
spots. When threatened by a predator, it dives into a crack in the
reef, leaving its hind end sticking out. Then the fish raises the
fins on its tail, back, and underside. This reveals a large black
spot surrounded by a white ring. Now the comet’s hind end looks almost exactly like the head of a whitemouth moray eel, a ferocious
predator that lurks in crevices on the reef.
Some reptiles also use mimicry. In southern Africa, a bushveld
lizard is camouflaged when fully grown, but it has black with
white spots and a dull red tail when it is young. This makes the
young lizard’s small body look like that of an oogpister beetle,
which sprays a smelly, burning fluid at predators. The little lizard
even walks like a beetle, with its tail held down so that it blends
in with the sand.
Scientists have found lizards in South America that mimic
invertebrates, too. One species of lizard curls its tail over its back
to show its orange underside when it is bothered. This makes it
look like a venomous scorpion. Another kind of South American
lizard has young that look like a poisonous millipede.
Some caterpillars mimic snakes, as do other snakes. The
false cobra of Asia, for example, is mildly venomous—its bite is
not deadly like a cobra’s. But when it is bothered, the false cobra
rises up, spreads its neck like a hood, and hisses loudly, just as the
real cobra does.
In North America, non-venomous bull snakes mimic rattlesnakes.
A bull snake does not have a rattle, but if threatened, it
will shake its tail rapidly. This rustles the leaves and grass around
it, and can startle a predator into thinking that it is dealing with
The most famous example of snake mimicry centers on coral
snakes. There are about 65 species of coral snakes found in parts
of North, Central, and South America. They are highly venomous
and clad in warning colors of black and red with yellow or
white bands. Snakes that share these colors are known as false
coral snakes. Some false coral snakes are mildly venomous. Others,
such as the scarlet king snake, are non-venomous.
For many years, scientists assumed that the coral snake was
the model and the other snakes were mimics. However, it may be that the mildly venomous false coral snakes are the models. A
bite from such a snake would hurt a predator, but not kill it. The
predator would learn to avoid such snakes in the future. These
would create a population of “educated” predators that have
learned to avoid red, yellow, and black snakes.
A bite from a deadly coral snake, however, would kill the predator.
This would mean that the coral snake could never “educate”
predators to leave it alone. Thus, the deadly snake may mimic the
less deadly one—it benefits from having the less deadly snake educate
the predators. The non-venomous mimics benefit, too.