In the animal world, bigger isn't necessarily better

Dec 11, 2008

Shocking new research shows size isn't always an advantage in the animal world, shattering a widely-held belief that bigger is better.

Michael Kasumovic, a former University of Toronto Scarborough PhD student, examined Australian Redback male spiders to determine whether the larger ones had an edge in achieving mating success and producing offspring.

Surprisingly, Kasumovic found the large spiders didn't always have an advantage. Instead, because the larger males experienced a much longer maturation process, they were unable to search for and mate with females and produce offspring at the same rate as the smaller Redback spiders.

"Most people assume that large size and weaponry are key indicators of a male's fitness, because those traits help them dominate smaller males," says Kasumovic, now a post-doctoral research fellow at the University of New South Wales. "However, smaller males develop sooner and are therefore able to mate with females before the larger males. So while large males may dominate in combat, they are unable to compete with the smaller males in terms of mate searching."

The study, currently published online in the Journal of Evolutionary Biology, emphasized the important role maturation time plays in defining a successful male.

"Size is no longer the only ruler by which we can measure a male's quality," says Kasumovic. "Many other factors, including maturation time, are critical in that definition."

Source: University of Toronto

Explore further: Retaining forests where raptors nest can help to protect biodiversity

add to favorites email to friend print save as pdf

Related Stories

Spider love: Little guys get lots more

Dec 08, 2008

Big males outperform smaller ones in head-to-head mating contests but diminutive males make ten times better lovers because they're quicker to mature and faster on their feet, a new study of redback spiders reveals.

Recommended for you

New tool identifies high-priority dams for fish survival

42 minutes ago

Scientists have identified 181 California dams that may need to increase water flows to protect native fish downstream. The screening tool developed by the Center for Watershed Sciences at the University ...

User comments : 0