Dancing Cockatoos and the Dead Man Test is the type of non-fiction book that I enjoy, with clear explanations about various subjects, while the author adds interesting and amazing examples of the how the world works. The author of this book is Marlene Zuk, who works as a behavioral scientist - at one point, she mentions studying crickets on the island of Hawaii. Male crickets sing to attract females, but on Hawaii there is a parasite fly that also is attracted to cricket songs - it drops its larvae on the male crickets back. When they hatch, they eat the male cricket alive. In Hawaii, some of the crickets have evolved (in relatively few generations) to be "flat-wings", which means that they are unable to sing. (Crickets apparently sing by rubbing their wings together). The flat-wing males find females by being drawn to the song of other males - they are "satellite" males - mating with females that are lured by the singing male. The "satellite" male strategy is employed by other species as well. The big question is: how do the flat-wing males learn to be drawn to the singing of other male crickets - is it instinct or a learned behavior?
The title of the book refers to cockatoos that listen to music and do dance moves to the music. If you look at on-line videos of Snowball the Cockatoo, there are 14 different dance moves that the bird has created. Where does this behavior come from? The Dead Man Test (sometimes less-gruesomely known as the Teddy Bear Test) says that if a Dead Man can do it, it isn't a behavior. The book has chapters on domestication, intelligence, communication, gender roles, fighting diseases. While some of this material might be important, it wasn't always amazing, which is why I awarded the book four stars instead of five. But the wealth of amazing facts makes the book a worthwhile read.
One species of ants preys on termites, but attacking termites is a dangerous task. Termites have powerful jaws and fight back. These ants will assess their wounded comrades, performing a battlefield triage, and if their injured comrade has only lost one or two legs, it will be carried back to the nest to heal. Ants that lose more than 2 limbs are left behind. When these ants head out to attack the termites, up to a third of them are missing at least one leg. The question: how do the ants evaluate whether they should abandon their wounded fellows? Are ants smart?
Black fire ants love sugar water. Normally, they can walk out onto the surface and slurp up the liquid, the surface tension is enough to support them. But diabolical researchers can add a fluid to the water that lowers the surface tension, the ants will drown if they enter the water. The ants use grains of sand at the waters edge to build a "siphon", so that the sugar water seeps up and the ants can feed safely. How do the ants know that the water will not support them? How do they know how to build siphons?
Clown fish live in small schools. The biggest fish is the dominant clown fish, and it is the breeding female. The second largest clown fish is the breeding male. If the female is killed, the male changes its sex and grows larger to become the dominant female, while one of the lesser clown fish will grow to become the male. This indicates that clown fish can determine their sex and how big they can grow.
When some chimpanzees feel sick, they will swallow (without chewing) the leaves of the Aspilla plant. An ill chimp can swallow more than 50 leaves. The leaves pass through the chimpanzee without being digested. Aspilla leaves are especially hairy - the chimps are trying to use the leaves as scrubbing brushes to scape parasites out of their digestive tract. How did the chimpanzees learn to do this?
Nicotine is similar to the toxic chemicals found in pesticides. Birds will pick up cigarette butts and line them in their nests if their nest is plagued with ticks or other vermin. How do birds know how to do this?
There is a parasite whose lifecycle requires it to reproduce inside a cat. The parasite eggs are expelled through the cat's feces, which then get into mice and rats. When the parasite grows, it needs to be back inside a cat, so somehow it hijacks the rodent's brain, causing it to become less afraid. Mice with toxoplasmosis are actually attracted to cat urine, which means that they are more likely to be eaten, which benefits the parasite, though of course it costs the mouse its life. (The toxins in the parasite eggs are dangerous to pregnant humans, which is why pregnant women should never clean the cat box). How can the parasite change the mouse behavior?
Researchers wondered if viruses could have an effect on human behavior. It is beneficial to viruses if their infected host is exposed to other humans, which would obviously increase its likelihood of spreading. The researchers asked volunteers to self-report their behavior 48 hours before and after getting a vaccine, and then 4 weeks after the vaccine shot. Vaccines administer weakened versions of a virus to a person so that their immune system can recognize the invader and learn how to fight it. So getting a vaccine is similar to getting infected. The research results showed that in the 48 hours after a vaccine, people did more social activities - going to parties and gatherings, etc. But 4 weeks after the shot, their behavior had resumed normal levels of sociability.
When I read a book like this, I am always surprised to learn of all the things people study, and the conclusions that they come to based upon their data. I should see if our library has any more of Zuk's books.