Monday, April 4, 2016

Deception!

If you saw Friday’s video about the device that converts octopus gestures into English, hopefully you caught on that it was a pretty good (and hilarious) April Fool’s prank by Oregon Sea Grant. Although there is not a lot of evidence of animals deceiving one another for fun, deception is pretty common in the animal kingdom. Here are some examples:

1) Male nursery web spiders often court females with gifts of a tasty fly wrapped in silk to appease her while he mates with her. But some stingy sneaks will eat the fly themselves and wrap up the carcass, or worse yet, wrap up some random piece of junk. If she tries to snatch the gift from him, he hangs on and plays dead until she stops running, only to “come back to life” to mate with her then.


2) Cowbird moms lay their eggs in the nests of other species, relieving themselves of parental duties. But they stack the deck in favor of their own chicks: they often push eggs of the host bird out of the nest and color their own eggs to match that of the host. Their eggs hatch sooner and their chicks grow faster than their “siblings”, which the chicks promptly push out of the nest to their death.

This is a picture of begging chicks in a parasitized nest of a chalk-browed mockingbird, taken from a video. The chick with the smaller, redder gape at the top of the image is the cowbird. The other larger gapes belong to the mockingbird's own chicks. Photo by Ros Gloag.

3) Crocodiles have been found to place sticks on their snouts to lure in birds that are collecting nest material.

I’m just a floating log and sticks… Really. Photo by Dinets published in Ethology, Ecology & Evoluton 2013

4) A queen ant wears a chemical disguise to smell like another species, only to sneak into their nest and lay her eggs for this other host species to raise. The queen’s offspring then grow into an army that enslaves their adoptive colony, to serve their needs for life.

A 1975 cover of Galaxie/Bis, a French science fiction magazine,
 by Philippe Legendre-Kvater. Image from Wikimedia.

5) The mimic octopus pretends to be venomous fish and sea snakes so predators will avoid it.

The disguises of the mimic octopus: (a) shows a mimic octopus looking out of its burrow; (b) is a foraging mimic octopus with coloration to blend with the sand; (c) shows a mimic octopus as a sole fish and (d) is an actual sole fish; (e) shows a mimic octopus as a lion-fish and (f) is an actual lion-fish; and (g) shows a mimic octopus as a banded sea-snake and (h) is an actual banded sea-snake. Images from the Norman, 2001 article in Proc. R. Soc. Lond. B.

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