Beaked whales

In our national newspaper the NRC of 3th May 2014 I read an article about beaked whales. Between the 1^st and 6^th of April, at least five Cuvier’s beaked whales stranded on Crete. Very likely a military exercise with sonar in the same week caused this multiple stranding.

This reminded me of another article I read in the ranger’s diary on the “kilda.org.uk” website (http://www.kilda.org.uk/frame2.htm). In September 2013 a beaked whale stranded with her calve on St. Kilda. The calve managed to get back to deep water, but the mother unfortunately died. The mother was still lactating, so the chances of survival for the orphaned calve was considered very poor.

The family of beaked whales or Ziphiidae is a whale family of which little is known. They are very shy and they hunt in deep sea. There are six different genuses of beaked whales and at least 22 different species, some of which have never been seen alive.

Beaked whales are a remarkable family. Most of them live solitary or in small groups up to four individuals. Scientists shot satellite transmitters in the skin of a group of Cuvier's beaked whales and discovered that beaked whales can dive up to 3,000 metres deep. They hunt for squid or deep sea fish using sonar and they can stay down for more than two hours.

Because lungs can’t resist the high pressure in deep sea, beaked whales use their muscles to store oxygen. The muscles of beaked whales can take a very 
high amount of oxygen which is used very efficiently.

Stranding of beaked whales is rare. Multiple strandings of beaked whales only occur when military exercises with sonar are held. These stranded animals almost always show internal bleeding in head, lungs or kidneys; possibly caused by caisson disease (decompression sickness), although normally whales are well adapted to prevent caisson disease.

The stranded animal on St.Kilda was a Sowerby’s beaked whale or North Atlantic beaked whale (Mesoplodon bidens). The whale was examined by the Scottish Marine Animal Stranding Scheme (SMASS). The examination hoped to establish the cause of death of this specific individual, and it would provide a lot of information about the species.

In the brain of this individual a blood clot was found. It is not clear whether this was the cause of the stranding or a result of the struggle of the creature on land.

For the ranger on St. Kilda it must have had mixed feelings; a unique chance to examine a rare, unknown creature, but unfortunately at the expense of a deceased individual and his orphaned calve.