Who do you think makes these tracks in the sand? Any guesses? Here’s another photo, taken from farther away to give you a bigger picture of the scale of things. Believe it or not, the maker of these trails is the little black turban snail, Tegula funebralis. They are one of my favorite animals in…
Marine invertebrates
Creepy crawlies
There are certain creatures that, for whatever reason, give me the creeps. I imagine everyone has them. Some people have arachnophobia, I have caterpillarphobia. While fear of some animals makes a certain amount of evolutionary sense—spiders and snakes, for example, can have deadly bites—my own personal phobia can be traced back to a traumatic childhood…
The tiniest advantage
Although the world’s oceans cover approximately 70% of the Earth’s surface, most humans interact with only the narrow strip that runs up onto the land. This bit of real estate experiences terrestrial conditions on a once- or twice-daily basis. None of these abiotic factors, including drying air, the heat of the sun, and UV radiation,…
My favorite larva — the actinotroch!
Five days ago I collected the phoronid worms that I wrote about earlier this week, and today I’m really glad I did. I noticed when I first looked at them under the scope that several of them were brooding eggs among the tentacles of the lophophore. My attempts to photograph this phenomenon were not entirely…
A different take on ‘vermiform’
If I asked you to draw a worm and designate the front and back ends, you’d most likely come up with something that looks like this: And you would be entirely correct. A worm, or any creature described as ‘vermiform’ for that matter, has an elongated, wormlike body. Some worms have actual heads with eyes…
Lunacies
For several centuries now, Earth’s only natural satellite has been associated with odd or unusual behavior. Lunatics were people we would describe today as mentally ill, who behaved in ways that couldn’t be predicted and might be dangerous. The erratic behaviors were attributed to the vague condition of lunacy. These words are derived from the…
The fluidity of sex
We humans are accustomed to thinking of sexual function as being both fixed and segregated into bodies that we designate as either Female or Male. And while we, as a species, generally do things this way, in the larger animal kingdom sexual function doesn’t always follow these rules. Many animals are monoecious, or hermaphroditic, having…
Now you see it, now you don’t
This morning in the intertidal I was reminded of how often I encounter animals I wasn’t looking for and almost missed seeing at all. That got me thinking about color and pattern in the intertidal, and how they can be used either to be seen or to avoid being seen. Some critters–the nudibranchs immediately come…
Peanut worms!
If I ask my invertebrate zoology students to name three characteristics of the Phylum Annelida, they would dutifully include segmentation and chaetae (bristles) in the list. And they would be correct. Annelids, for the most part, are segmented and many of them have chaetae. But in biology there are many exceptions for every rule we teach,…
Eight is enough
One of the defining characteristics of the Phylum Mollusca is the possession of a shell, which serves both as a protective covering and an exoskeleton. We’ve all seen snails, and some people may have noticed that snails often withdraw entirely into their shells and even have a little door that they can use to seal up the…