Two Lost Whales
You’ve probably heard about this already; it’s been in the news on and off for the last few weeks. Two humpback whales swam up the Sacremento River, and hung out for a while. Here is a news article about them:
http://news.yahoo.com/s/ap/20070521/ap_on_re_us/delta_whales
It’s not really unusual for large whales to come close inshore; it is unual for them to swim upriver so far. The last tiem a humpback spent so much time in the Sacremento River was in 1985. The two whales this time are apparently a mother and calf, and made it more than 20 miles upstream before they turned back to head for the ocean.
As the article notes, they both have wounds which may have come from boat propellers. This is a common hazard for inshore aquatic mammals. In south Florida, where a lot of people have boats, and a lot of boat channels are inhabited by manatees, propeller injuries are common. Even dolphins, cetacean relatives of humpback whales, are sometimes hit by boats.
Whales like these, however, are less frequently injured by boats. For starters, humpbacks are big, up to 60 feet long, making them easy to see. Also, these large whales can dive deeper, and stay down longer, allowing them to avoid surface craft.
It’s not likely that the propeller wounds will prove life-threatening to either whale. Whales in general, and large whales in particular, possess thick layers of blubber directly under their skin, which serves the dual purpose of insulating the animal in cold water and armoring the animal against injuries. Blubber injuries to whales usually heal and leave the animal with no lasting problems. The main problem with such injuries is infection. This is more of a problem for these whales, since the river they’re in now is not as clean as the open ocean.
I’ll post more about these whales later, if they ever decide to leave leave the river…
