Subject: Re: My Whale Question

Steve Frohock (Sfrohock@tiac.net)
Sat, 26 Oct 1996 10:55:05 -0700

Stephanie Dunbar wrote:
> 
> Hi Steve!
> 
> I understand that you are the official answer man for all
> whale-related questions.
> 
> I would like to know why whales jump up out of the water.  It seems as
> though it would be a great effort for them to do this given their
> large size and weight.
> 
> Thank you!
> 
> Stephanie 
Hi Stephanie,

There are a number of theories about why whales breach (jump out of the 
water). Most center around social display and communication that can be 
used extensively in aggressive or competitive situations. Through the 
evolutionary process, most animals have developed display systems to 
avoid confrontations that can cause physical injury. It is likely that 
breaching is one of these mechanisms. Only when animals are very evenly 
matched do they resort to actual "fighting". Humpbacks have been known to 
actually breach on top of a competitor during these fights. 

Breaching occurs most frequently during the winter months when the 
humpbacks are courting and mating. Large groups of males get together to 
sort out dominance hierarchies, which can lead to increased mating 
success. Breaching plays an important role in this competition.

During the summer months, while humpbacks are feeding rather than mating, 
whales breach less frequently and the function is not so well defined. 
Scientists believe that it still relays social messages in many 
situations but there are many other possibilities. One is play. Often 
young whales (either new borns or juveniles) engage in extensive surface 
displays. Like all young animals, young whales tend to be more "playful" 
than the adults. This is almost certainly exercise or learning behavior. 
Dominance display is also believed to be a factor during the summer 
months.

Steve