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Brain size can vary tremendously between species. For instance, the average human head holds around three pounds of cerebral matter; your typical chimp, on the other hand, packs about a third of that. More »
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Female chickens are among the most promiscuous members of the animal kingdom, with wild and domestic fowl alike tending to mate with way more males than necessary to fertilize their eggs. More »
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To compete for mates, male beetles often grow fierce mandibles that they use to fight other males. Unfortunately, there's a tradeoff. Researchers in Japan discovered that beetles with longer mandible weapons have smaller testicles and less ejaculate than their brethren. More »
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Among the tiny insects known as water striders, males who aggressively attempt to mate with females don't wind up with as many offspring as their more gentlemanly counterparts. How can aggressive mating ever be a losing strategy? More »
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Accepted scientific wisdom holds that new species arise because of geographic separation - the same bird evolves differently on two different islands. But a new study overturns this idea, challenging the importance of environment as a driver of evolution. More »
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Seed beetles are polyandrous – females mate with multiple males, and choose which sperm will fertilize their eggs afterward. Scientists long believed they did this to get the best sperm. But a new study shows the fittest males always lose. More »
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Scientists have known for a while that humans seem to pick mates partly based on the way they smell. That's because a person's smell is related to their Major Histocompatibility Complex (MHC), a cluster of genes that shape a person's immune system. For years, scientists have debated whether people pick mates based on scent cues that indicate a potential mate has a very different MHC, which would give children a higher possibility of developing a robust immune system. And now a new study published in PLoS Genetics today shows that certain human populations are clearly following their noses to the wedding bed. More »
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If you watch enough TV, you get the idea that the ideal mating combination is a skinny little woman and a burly man. But a new evolutionary study published in American Naturalist shows that's not what nature intended. In fact, the humble New Zealand weta (a relative of the cricket) demonstrates that evolution often pushes in the other direction: Only the smallest and most nimble weta males get to score with the sexy weta ladies who are twice their size. How could tiny males impress the weta females? More »
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