Friday, February 25, 2011

Whale Washing Videos.

Here are some links to videos about the work we are doing in the Whale Hall.

Just click on the title:
Hvalrens 2010

Hvalvask

Whale Washing (English)

Monday, February 14, 2011

How old are the whales?

We know the history of the whale hall, the date the whales were collected and which species each whale is but what we don’t know is how old the whales are. Are they baby whales or grandma whales? How can we tell?

The answer is in the morphology of the bones. The vertebrate skeleton (such as a whale’s) begins as cartilage which is then ossified (replaced by bone) as the animal grows. However at the top and bottom of the bones a strip of cartilage remains, this is known as the growth plate.

This cartilaginous plate provides a growth zone in an otherwise fully ossified bone allowing bones to increase in length and size during development. The cartilage grows continually and is steadily replaced by bone until a final size has been achieved, then the remaining cartilage will stop duplicating and is ossified, permanently closing the growth plate.

By examining the whale skeletons and looking for growth plates – which will look like gaps in specific parts of the bones as the cartilage is not longer in situ – we can tell if the individual was still growing or was a fully grown adult.
After close examinations of all 8 whales in the hall we found that every one of the whales had open growth plates in one or more bone – we found them in the vertebrae, scapular, ulna, radius, and humerus. This indicates that all of the whales were still growing and although we cannot give them a specific age we know they were not fully, skeletally mature.


Unfused growth plates in caudal vertebrae. Indicated by white arrows. Sei whale.



A close up of the unfused vertebral gowth plates. Sei whale.



Growth plates at the humerus, ulna and radius. The ulnar plate is partially fused. Sei whale.



A close up of the growth plates at the elbow.

Catherine, the anatomist on the team is currently researching how we can use the growth plates that have been found to provide a more specific age for each whale. The use of ossification status has been extensively researched and utilised to estimate chronological age in many mammalian species but due to the obvious limitations in studying the skeletons of these huge, rare, aquatic animals more research, such as that being carried out here in Bergen whale hall is required to answer our questions about whale age.

A Whale Hall Update and A Surprise Discovery

We have now cleaned three of the largest whales in the collection, a Northern Right whale, a Humpback whale and a Sei whale and we are in the process of cleaning the equally massive Finn whale. There is still some work to be carried out these skeletons as we will fill in cracks found in bones, repalce missing parts of bones and re-articulate some of the ribs which were removed for cleaning.

Things are going well and we are continuing with the wet cleaning methods we have refined over the previous months. Currently we are working on the tail (caudal vertebrae) and ribs and so far, although very dirty, this skeleton does not appear to be very oily in comparison to the others.

Whilst cleaning the tail vertebrae Marielle has come across something very interesting…..

On the dorsal surface of the lateral process of the 41st vertebrae she saw something under the dirt scratched into the surface of the bones – as she rubbed away some of the dirt it become clear…



It would appear that one of the people preparing this whale skeleton has scratched his or her initials and date into the bone – a very interesting, and very old, artefact and a very special connection to the person who was last cleaning these bones over 100 years before Marielle. You never know, there may be more surprises under the dirt as we continue…