humans

This year's flu season is going to be bad. So far, at least 30 children have died from the flu.

But, as it turns out, influenza won't be bad just for humans; it will be bad for our canine companions, as well. According to news sources, canine influenza ("dog flu") has been reported in 46 states.

Dog flu is incredibly infectious. Though there is no "dog flu season," the American Veterinary Medical Association (AVMA) says that nearly all dogs that are exposed to it will become infected, with 80% showing signs of illness. Symptoms in dogs are similar to those seen in humans: fatigue,...

Humans have a much longer and wider penis than the other great apes. Even the largest of gorillas, more than twice as heavy as a human, will have a penis just two and half inches long when erect.

However our testicles are rather small. A chimpanzee’s testes weigh more than a third of its brain while ours weigh in at less than 3%. The relative size of our penis and testes is all down to our mating strategies, and can provide some surprising insights into early human culture.

Primates exhibit all sorts of mating behaviour, including monogamous, polygynous – where males have multiple mates – and multimale-multifemale. One indicator of which behaviour occurs in a species is the size difference between males and females. The greater this...