Colour and Camouflage

http://www.cephbase.utmb.edu/viddb/vidsrch3.cfm?ID=132

• Color has been used for millions of years for: Protection Camouflage Intimidation

• Camouflage: when an animal uses other organisms, sand, rocks and plants that are common in their environment to blend in

• Intimidation: use of bright colors to advertise being poisonous.

http://www.reefimages.com/Camouflage/camouflage_index.html

http://cas.bellarmine.edu/tietjen/Animal%20Behavior/cool_cephalopod_vids.htm

Methods of deception:1. Be transparent: your

predator looks through you rather than at you (used among some jellyfishes and zooplankton)

2. Countershading: the back of the animal is dark colored and the belly is light colored.

Some fish also have slivery sides that reflect light or distorted coloration patterns or vertical bars that help break up their outline (like a zebra).

3. “Fake eye”: Some small fish have a dark spot near the middle of their body which makes them appear to be a larger fish.

4. Blending in: looking like your surroundings

5. Intimidation: This method is used when an organism wants to advertise that it is poisonous. This is done through the use of bright reds and yellows mostly.

Some reptiles, fish, and amphibians can change colour almost instantly, at any time of the year, to blend in with many different backgrounds.

Example: octopus and flounder

• These animals have chromatophores, or color changing cells, in their skin that can contract or expand to make the animal change color.

• Chromatophores are irregularly shaped, pigment-containing cells

Orange and black spots are chromatophores

Two spot octopus, seen above as orange, and to the right as brown, has the orange chromstophores ``off``

The blue spots are actuallyFalse eyes. The real eyesare above the spots.

• When an octopus is camouflaged on a bumpy rock, it will change not only its color but also the texture of its skin, going from smooth to pebbly to better match the rock! 

• When threatened, an octopus will quickly turn a whole series of different colors, from pink to tan to grey before it makes its escape in a cloud of ink.

Mimics:

• The phenomenon where a species evolves to resemble another species (the model) for gaining some biological benefit is called mimicry.

Mimicking a sea snake

Worm mimicking a nudibranch

• DO NOT COPY THIS SLIDE!!!!!

19 January 2005 - Senior scientist Roger Hanlon and his colleagues at the Marine Biological Laboratory (MBL) reported in this week’s Nature that male cuttlefish use sexual mimicry to successfully impregnate females. The proof that this technique can be successful offers incentive for future study of mating systems.

The MBL group studied the Australian cuttlefish, for which mating is highly competitive. The male to female ratio is about four to one but can get as high as eleven males to one female. Because of this, consort males (males with female partners) guard their mate almost constantly.

Large consort males mate the most, forcing smaller males to use trickery and mimicry to mate at all. The techniques used by small males include waiting until the consort male is distracted by repelling other competition, waiting for females under rocks, or making themselves look and act like females to get close to females. When mimicking they get close to females about half of the time.

“The level of sophistication of mimicry is amazing," Bryan Neff, a behavioral ecologist at the University of Western Ontario told Nature.

To mimic females, males hide their fourth arms, adjust the pattern on their skin, and act like egg-laying females. Male mimics can change their appearance 10 to 15 times a minute.

“In the blink of an eye they can pull out of it and go back to being a male,” Hanlon said in the press release.

In this study scientists used DNA testing to prove the paternity of eggs laid by females who mated with male mimics.

"We're providing genetic proof that sexual mimicry leads to immediate fertilization success," Hanlon reported in the release. Journal of Young Investigators. 2005. Volume 12.Copyright © 2005 by Nicole Fahrenfeld and JYI. All rights reserved.

Close-up

WARNING!!

Poison!!

Humans using camoflage…

hahahaha

• http://videos.howstuffworks.com/discovery/29076-the-ultimate-guide-octopus-cuttlefish-camouflage-video.htm (cuttlefish)

• http://videos.howstuffworks.com/discovery/28236-assignment-discovery-octopus-camouflage-video.htm (blue ring octopus)

• http://www.mnn.com/earth-matters/animals/videos/camouflage-scheme-squid-glows-to-escape-predators (bobtail squid)

• http://www.youtube.com/watch?v=k8RlGbpuhgc

JOURNAL PROMPT

• Write down three examples of aquatic creatures using camouflage and explain what you learned about these scenarios from the videos and article.