Predators tend to target young animals because they are easy prey. If young are born asynchronously, predators can eat a ...

New research shows that birds investing more energy in reproduction age faster and live shorter lives than those investing less.

If you've ever had a spiny leaf insect as a pet, or you're considering getting one, hopefully someone has warned you about this: if you put one in your enclosure, you might come back some time later ...

The energy invested in animal reproduction is as much as 10 times greater than previously estimated when the metabolic load of bearing and caring for offspring is accounted for, according to a new ...

An Asian water dragon hatched from an egg at the Smithsonian National Zoo, and her keepers were shocked. Why? Her mother had never been with a male water dragon. Through genetic testing, zoo ...

(Santa Barbara, Calif.) Why are most organisms sexual? The question of why most species reproduce sexually and others reproduce asexually has stymied biologists for years (particularly since asexual ...

Elephants are pregnant for up to two years. Females of some fish species starve for weeks while holding dozens of eggs and hatchlings inside their mouths. And pregnant humans commonly endure months of ...

Two novel hypotheses have been proposed that address the 'two-fold cost of sex': one of the biggest enigmas in the evolution of sexual reproduction. Two novel hypotheses have been proposed that ...