No one is exactly sure why the tigers of the Sundarbans are so aggressive towards humans, but scientists, biologists, and others have speculated about a number of reasons.

Some biologists speculate that they do this so that their mothers would be willing to mate again more quickly.

Some biologists have speculated that these advertisements may not just tell a parent which offspring are hungry.

I don't believe that biologists speculate that any aspect of the code was "designed."

Presence of a beard makes the owner vulnerable in fights, which is costly, so biologists have speculated that there must be other evolutionary benefits that outweigh that drawback.

There is always plenty of water in that region, but the fertility of its lakes and ponds is generally low and some biologists speculate that the birds find it difficult to nest in unfamiliar territory.

A few theories: The Victorious Immune System: Evolutionary biologists speculate that a hypersensitive immune system was needed back when parasites were ubiquitous and deadly.

Earlier in the day, biologists speculated that the whale might have followed krill or another food source into the Gowanus Canal, whose polluted waters have cleared somewhat in recent years.

Since the identification of CTR1, biologists have speculated that a MAP kinase cascade may be involved.

Cape Cod's marine biologists who specialize in the study of whales, porpoises, and dolphins could only speculate last week about reasons for the blue whale visits.