Parking Lot Ecotourism

Look what we saw from my office window today!

It seems that the two-toed sloths like to forage in that particular tree. Someone told me that sloths especially like the white flowers on these trees, but from here I can’t see any flowers.   I most often see the sloths around 4pm, just after the students leave for the van that takes them back to the city.  Sloths aren’t social but there are usually two together, and I wonder why; are they mother and baby? They look too close in size for that.  Friends? Competitors, each one trying to get to the best leaves first?

For marine biologists it is fantastic and a little bit unusual to be so close to forest animals. Because the island is so small, wildlife from the seasonal dry forest on Naos and Culebra often venture down into the parking lot. And they come close to the office windows. So we can see some nice animals from the comfort of our office chairs. It makes a nice break.

We often see green iguanas sunning themselves on the roofs. It’s a treat to see a large male climbing up the papaya trees around the lab. They feast on the fruit as they ripen, leaving none for us.

Green iguana and papayas

In the early evening it’s common to see armadillos at the edge of the shrubbery. Bats come later to feed on the fruits of the sea almond trees planted around the parking lot. At night they are just a flurry of wings in the dark, but in the morning we find the chewed fruits lying under the trees.

Nine-banded Armadillo

We are also surrounded by numerous smaller animals: lizards, song birds, myriad insects, spiders, scorpions….  Even though we are biologists, few of us stop to observe these less obvious animals.  We keep our heads down as we hurry from the parking lot to our offices in the morning or head home at the end of the day.  But who doesn’t stop to watch a sloth?

Introducing Slipper Snails

A lot of the research in the Collin Lab focuses on slipper snails (sometimes called slipper limpets or slipper shells).  I like to refer to them as slipper snails because they are more than just a shell; they are really cool and complicated animals. 

The Latin name for the genus of slipper snails is Crepidula.

Slipper snails and their relatives all belong to a single family, the Calyptraeidae.  Future posts will explain the questions we are trying to answer, the methods we employ, and some of the things we have discovered. But for now, here are a few quick facts as an introduction to my favorite snails.

New species are being discovered all the time. At the moment, there are about 200 species of calyptraeids.  That is, there are 200 species that have been officially described and named, and which biologists agree represent distinct species.  But nobody really knows how many species have yet to be discovered.

I described and named Crepidula ustulatulina in 2002.

Slipper snails change sex.  Small young animals first develop as males. As they grow they gradually change to become female.  Once female they cannot change back.  This kind of sex change - from male to female - is known as protandry.  Sex change from female to male, which is seen in a number of fishes is known as protogyny.

Slipper snails do not move around much. They don’t have to because they are filter feeders –in other words they filter particles out of the water for food – so they don’t have to search for food.   They attach themselves to the substrate and hunker down in the face of adversity. 

They often just look like bumps on a rock.

The most important aspect of calyptraeid biology, from the point of view of our research, is that slipper snails display an amazing diversity in how they develop from eggs to adults.  Some species have swimming larvae, some species have large eggs that develop directly into juveniles that look like small adults, in some species the embryos actually eat their siblings as they grow, and in other species the kind of development can change during the life of the mother.