Weddell Seals: Mating

ambience: Weddell seals calls

Weddell seals spend much of their time either above or below solid sheets of ice attached to the Antarctic continent. And their passage between the world above the ice and the underwater realm has some serious consequences for their species. I’m Jim Metzner, and this is the Pulse of the Planet. After spending nearly 50 days weaning her young on the ice sheet, a mother weddell seal replenishes her blubber reserves by diving into the water in search of fish and other prey. Well, male Weddell seals are waiting nearby under water because they know the female is in heat. Mark Hindell of the University of Tasmania in Australia tells us how the seals’ habitat influences their mating behavior. The “fast ice” he refers to is the solid ice attached to the Antarctic coastline.

“So we have these huge expanses of ice with no open water at all. All the other seals either breed on floating ice, with easy access to water, or actually on beaches and things. So these guys, breeding on fast ice, it sets the scene for their whole mating system because the whole thing is dominated by the fact that the females only have access to the water that they need to get into at one or two points. And that means the males can strategically defend those points.”

When winter arrives, the male Weddell seal may gnaw several holes in the sea ice with his teeth, working along an existing crack. Then he waits, and if he’s lucky, he’ll get to mate with a female Weddell seal that chooses to use his hole to enter the water. But whether he mates or not depends upon his ability to fend off other mails and defend his underwater territory.

We’ll hear more about Weddell seals in future programs. To hear about our new CD, please visit pulseplanet.com. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.

music

Weddell Seals: Mating

The mating game -- Antarctic style.
Air Date:07/14/2003
Scientist:
Transcript:


ambience: Weddell seals calls

Weddell seals spend much of their time either above or below solid sheets of ice attached to the Antarctic continent. And their passage between the world above the ice and the underwater realm has some serious consequences for their species. I'm Jim Metzner, and this is the Pulse of the Planet. After spending nearly 50 days weaning her young on the ice sheet, a mother weddell seal replenishes her blubber reserves by diving into the water in search of fish and other prey. Well, male Weddell seals are waiting nearby under water because they know the female is in heat. Mark Hindell of the University of Tasmania in Australia tells us how the seals’ habitat influences their mating behavior. The “fast ice” he refers to is the solid ice attached to the Antarctic coastline.

"So we have these huge expanses of ice with no open water at all. All the other seals either breed on floating ice, with easy access to water, or actually on beaches and things. So these guys, breeding on fast ice, it sets the scene for their whole mating system because the whole thing is dominated by the fact that the females only have access to the water that they need to get into at one or two points. And that means the males can strategically defend those points.”

When winter arrives, the male Weddell seal may gnaw several holes in the sea ice with his teeth, working along an existing crack. Then he waits, and if he’s lucky, he’ll get to mate with a female Weddell seal that chooses to use his hole to enter the water. But whether he mates or not depends upon his ability to fend off other mails and defend his underwater territory.

We’ll hear more about Weddell seals in future programs. To hear about our new CD, please visit pulseplanet.com. Pulse of the Planet is made possible by the National Science Foundation. I'm Jim Metzner.

music