Monday, February 28, 2005

Animal of the Week February 28, 2005 -- Giant Clam

This week's animal of the week is Tridacna gigas (giant clam). These tropical bivalves are the heaviest of all the molluscs (mysterious/fictional giant squid notwithstanding), they grow up to 1.3 m across and can weigh up to 250 kg (that's 4'4" and 550 lb for our imperial American friend). Although depicted in many an adventure story trapping the foot of a happless pearl diver, there is not a single documented case of someone being drowned by a giant clam, indeed some of the largest ones can't close there valves fully. Instead of dining on divers extremities, giant clams obtain most of their food from symbiotic algae (zooxanthellae), although Tridacna gigas does obtain some (~10%) of it's nutrients by filtering phytoplankton and zooplankton from sea water. These clams live in shallow coral seas and are found no deeper than 20 m below the surface. They breed by ejaculating vast numbers of eggs and sperm into the sea, which makes me wonder about the diver in this week's picture.

Monday, February 21, 2005

Animal of the Week February 21, 2005 -- River dolphin


First of all, my apologies for the lateness of AOTW, obviously the biggest losers are the animals which only get the title for a few days. I hope never to be so tardy again.

This week's animal of the week is Inia geoffrensis (Amazon river dolphin or boto). Botos are the the largest river dolphins (other species found in South and Central America and Asia) and reach a maximum size of about 2.5 m. These are some of the only dolphins that can bend their necks, as the vertebrae aren't fused. From the mouth of the Amazon to the foothills of the Andes, botos—which can be bright pink in colour (although white is more common)—feature strongly in Amazon folklore, some indigenous people believe botos can transform into human form at night, come onto land, and cause harm to people who have been naughty (or twee). When the river floods, botos leave the chanel and swim among the tree trunks and low branches of the forest in search of a fish supper.

Monday, February 14, 2005

Animal of the Week Ferbuary 14, 2005 -- The most dangerous animal in the world

This weeks animal is the most deadly of all the animals, but it also pretty small. Human malaria is cause by four different species in the genus Plasmodium. Plasmodium falciparum is the most dangerous of these species. There are upwards of 300 million cases of malaria (~5% of the world's population) and in excess of 2 million malaria deaths each year. The picture here is of a macrogametocyte among some human blood vessels. The male and female Plasmodium gametocytes are taken up by female mosquitos when they drink human blood, there the males parasites fertilise the females, progeny develop, and these then migrate to the mosquito's salivary glands... etc etc etc

Monday, February 07, 2005

Animal of the Week February 07, 2005 -- Alligators

Before this date AOTW existed, and I know what the animals are from the dates of when the images were saved, unfortunately, I had no idea that AOTW would become a blog and I didn't keep them all.
I posted the AOTW from an internet cafe in New Orleans on the day before Mardi Gras 2005. I had by then tasted alligator stew. It was quite delicious.
I probably said something about distinguishing alligators from crocodiles. With their mouths closed you cannot see the teeth of alligators, whereas crocodiles' bottom teeth stick out.
Otherwise who knows. I had a great time in New Orleans, amazing. I feel so very lucky to have been able to go to what will likely turn out to have been the last proper Mardis Gras.