biology zoology blog autotomy crabs claw legs

Autotomy : The Eggs -and not the Legs- Have it

Although nobody likes to encounter a crab when relaxing on the beach or entering the water for a swim, crabs are definitely worth a closer look. They are all supposed to have 10 legs (four on each side for walking plus a pair of claws, also called pincers, nippers, or chelipeds). But take a closer look: do all crabs really have the full complement of appendages? No, they don’t; often legs are missing and in some cases, you might find only a tiny leg where you’d expect to find a big one. What’s going on? Is that another thing we can blame on global warming? —>—>

zoology biology benno meyer rochow science blog vision eyes fish blind Florian Nock

Seeing is Believing

Fish without eyes

It is sometimes quite shocking what some people think the work of an animal biologist consists of. One day, when visitors to our house took a look at my aquarium and admired the fish in it, my ears had to hear the following comment: “Very interesting, but doesn’t it hurt them when you remove their eyes?” “What do you think?”, came my reply, “they are blind fish. They never have any eyes! They are Mexican cave fish, Astyanax mexicanus.” Stupid visitors (I did not say that), but they obviously did not know that some species of fish are naturally eyeless.

zoology biology benno meyer rochow science blog life sand Florian Nock

Microscopic organisms : Life’s Secretive Pioneers

Life’s Secretive Pioneers in the Sandy Pits

Many animals love to explore or spend most of their lives in the gaps and spaces created by piles of stones or wood: some cats like confined spaces, mice certainly do, and ants just love them. But ants can, of course, make use of much, much smaller crevices than bigger animals can. However, what about the sand on the beach? It is fine and seems compact, but there is always a small volume of interstitial space between the sand grains: could anything possibly be living in there? I bet no beach-frolicking folk ever think about that, but sure, further down the beach towards the sub-littoral you can step on shells buried in the sand and may get bitten on the toe by a crab that has sheltered in the substrate while further up, along the zone of decaying algal debris, you may encounter beach-hoppers and sand flies. But in between these two horizontal layers, would there be any life at all in the sand? —>