ZOO-ology column: Mimicry models of the natural world
Oct. 16, 2011 at 5:16 a.m.
Semiotics Encyclopedia Online; Mimicry-Wikipedia; Batesian Mimicry-Wikipedia; Muellarian mimicry (biology) Britannica Online Encyclopedia
By Judie Farnsworth
It's the time of year when people start thinking about Halloween costumes. Nature (a master of disguise) has taken care of that for some creatures.
The use of mimicry in the natural world can be a trick to keep from being another creature's treat. Mimicry is more complex than it first seems with many overlapping areas. In hopes of encouraging further learning, let's keep it as simple as possible.
Mimics are visible. They use signals; appearance, behavior, smell, taste, sounds and locations, to discourage predators or hunt. The one being copied is the model, the imitator is the mimic. Then there is a signal receiver or dupe. That's the one that is fooled (and hungry or worse).
Batesian mimicry - This could be the coral snake and scarlet king snake. Two or more species resemble each other, but only one (the model) is armed and dangerous. The mimic relies on its fortunate looks for safety. The hognose snake is a super mimic. It hoods its head like a cobra and shakes its tail like a rattlesnake.
Muellerian mimicry - This could be the monarch and viceroy butterflies. Two or more species share both similar appearance and defense. These butterflies have similar colors and both are toxic and nasty tasting to predators because of the plants they eat as caterpillars. Butterflies that mimic them are often left alone.
Emsleyan/Mertensian mimicry - This gets us into some overlapping. Basically it's when both a harmless and deadly species mimic a somewhat dangerous species. The scarlet king snake, coral snake and false coral snake are examples. The false coral snake bite can make an animal very sick, but it may live to "spread the word."
Mimics of the false coral snake may have a more hassle-free life as other species learn to avoid the red, yellow and black colors of all.
Peckhamian mimicry - A predator mimics a harmless species - the wolf in sheep's clothing! There's an unprincipled female lightning bug that mimics the blinks of another species. The love smitten unsuspecting males that come calling, are eaten.
Large eye-spots on moths, butterfly wings or fish tails can trick a predator into thinking - that's the head, go for it. That false target is called self-mimicry. It may also startle a predator allowing time for escape. There's even a snake in Africa whose tail looks and moves like a head, while the head looks like a tail.
Playing dead is a form of mimicry. The hog-nosed snake rolls on its back and oozes a foul-smelling fluid. Sometimes its tongue lolls out. Predators usually lose interest in something that looks and smells dead. The opossum is another animal famous for this trait. There are so many examples of mimicry and its super interesting. I hope you'll want to learn more.
Who will you mimic for Halloween? Bring your younger family for a friendly Zoo Boo trick-or-treat happening between 10 a.m. to 3 p.m Oct. 28 and 29, regular zoo admission. When darkness falls, visit the Haunted Zoo - admission $5 each, 7 p.m. to 11 p.m., Friday and Saturday and Oct. 28 and 29. It is not recommended for young children.
Judie Farnsworth is a longtime volunteer at the Texas Zoo specializing in educational programs.