May 31, 2010

Prolific Past 9 Days

Its been a prolific past 9 days marred by only been 1 day whale-less day. We've been blessed by humpbacks, transient orcas and resident orcas. For the past few days we've seen the easily identifiable T-40. Transient male dorsal fins can get up to 6 ft. tall and T-40 is all male. Born in 1961, the tip of his dorsal fin is dropping with age. It creates a natural umbrella handle or hook. Over the past few days he has been traveling with 2 companions, possibly both females or juvenile males, or a female and juvenile male.

Orcas have similar life cycles to humans. They live to be the same ages, reach puberty and sexual maturity at the same ages, the females have a long post reproductive life (which is unusual in animals other than humans and elephants), mate year round, and give birth year round. When the males reach puberty, their dorsal fin starts sprouting. Usually we can't tell the gender of a calf until its reaches puberty, unless we get a photo of their white underside, for example when they breach. Then we can see the markings of their ventral area and discern whether there are any mammary glands.

Maybe T-40 will continue to grace us with his presence...or maybe the residents are on their way back. Its been observed that the transients yield to the residents when they're in the area, possibly because residents travel in much larger groups than the transients, therefore presenting a larger threat. Transients eat other mammals including whales and dolphins, so it is counter-intuitive in some ways that the transients may be threatened by the residents. But there are 89 members of the Southern Resident Community, and Transients rarely travel in groups larger that 12, sometimes even traveling alone. T-14, Pender as he is also known, circumnavigates San Juan Island.

Transients rarely ever breach and today I saw one breach for the first time. We also saw several spy hops as well. All of the behavior that one sees at Sea World is based on natural behavior, but the mammal eating transients are simply less acrobatic than fish eating residents because mammals are much more perceptive than fish. Sound travels about 2 miles per second underwater, so the sound of their whole 12,000 pound body slapping the water during a breach could travel for 7 miles, alerting every marine mammal in the vicinity of their presence. Last evening when I saw them, and again today, this group of 3 transients seemed especially relaxed and playful. Swimming closely, caressing, tail lobbing, pec slapping, spy hopping and finally breaching, I think some courtship behavior may be involved.