It’s time to revisit that grand old parasite, the brain-infecting Toxoplasma. The more we learn about it, the more marvelously creepy it gets.

Toxoplasma is a single-celled relative of the parasites that cause malaria. It poses a serious risk to people with compromised immune systems (for example, people with AIDS) and fetuses (which is why pregnant women need to avoid getting Toxoplasma infections). If you’ve got a healthy immune system, it doesn’t cause any immediate harm. (Ed Yong has explained why a purported link to brain cancer is very weak.) All told, perhaps a quarter or a third of all people on Earth carry thousands of Toxoplasma cysts in their heads. Most never become aware of their living cargo.

Continue reading “Fatal Attraction: Sex, Death, Parasites, and Cats” →

The biggest animals on Earth–the biggest animals to have ever lived, in fact–are baleen whales. They can grow to over 100 feet long thanks in part to their ability to snarf colossal amounts of food. To do so, they swing open their toothless lower jaws, which inflate like a parachute with water. Then they haul their lower jaw shut again and then use a titanic tongue to push out a school bus worth of water through a filter. The filter is baleen: a set of fronds that hangs from their upper jaws. They trap shrimp and other tiny creatures in the baleen, which the whales then swallow before preparing for the next gulp. Each one of these operations can snag a blue whale up to half a million calories.

Continue reading “Before Leviathan” →

I learned that Google has retooled its invitation system for Google+. Instead of manually adding names into a message field, I can just drop a link into this post and offer 150 invitations. So if you want to dabble in this new experiment in social media and enforced non-pseudonymity, please click here.

Originally published August 8, 2011. Copyright 2011 Carl Zimmer.