9/18/11

LAP: Eastern Box Turtle, Part II

This is the second post about the newest animals to appear during the Aquarium's Live Animal Presentations. Get up to speed on Eastern box turtles in this previous post.

Road separating habitat
Although they have a variety of habitats, box turtles greatest threat is habitat loss or fragmentation.


Eastern box turtle. Photo courtesy Jarek Tuszynski via Wikimedia Commons

Fragmentation occurs when habitats are separated by land that humans have developed. The fragmented habitats tend to be very small, resulting in a loss of biodiversity. When confined to smaller areas, turtles may have a difficult time finding food or mates and as a result may suffer from inbreeding and other genetic problems. Massachusetts alone loses about 40 acres of natural habitat per day to development (Mass Audubon Study from 2003).


Photo courtesy Tysto via Wikimedia Commons

Roads are one of the greatest dividers of habitats. Box turtles sometimes use less-than-ideal routes to avoid roads which may increase the risk of predation. Many female turtles looking for nesting habitat cross roads and are killed by cars, reducing the breeding population. One solution to the problem of habitat fragmentation is to link the fragments by preserving or planting corridors of native vegetation. In the case of roads, underground tunnels can be dug to connect habitats. Do you think this is a good
idea? Can you think of other solutions? Here are some more ideas to help turtles…
  • Restore vegetation (like your yard) to a more natural state. Use native plants!
  • Mow only in the hot afternoon, when turtles are less likely to be out
  • Avoid using herbicides, especially on fruiting plants.
  • Keep pets on leashes
  • Protect habitat from development: contact the Wildlife Land Trust or Nature Conservancy to help purchase and preserve land where box turtles occur
  • _______________ (insert your idea here!)
Reproduction
Box turtles reach sexual maturity at about 5 to 10 years old. In Massachusetts, females usually don’t lay their first clutch until 14 years of age. Females can store sperm for up to 4 years! They sometimes travel up to a mile to find suitable habitat and lay between three and six eggs each spring in a shallow nest. The eggs are left unguarded and hatch in summer to early fall. Over the span of one lifetime, females lay hundreds of eggs, but only two or three will survive to adulthood. These eventually replace their parents in the population. However if box turtles are removed from the wild, this reduces the breeding population, creating a decline in total population numbers.


Photo via Wikimedia Commons

Boy or Girl?
  • Male box turtles have wider tails, more flattened shells, and dark orange or red eyes.
  • Females box turtles have brown or light orange eyes.
Because box turtles are long-lived (30-50+ yr. lifespan), slow to mature, and have few offspring, their population is vulnerable to habitat disturbances, motorized vehicle kills, high levels of predation, and loss of individuals through the pet trade. Eastern box turtles are listed as a Species of Special Concern in Massachusetts and are protected from commercial trade under CITES (Convention on International Trade of Endangered Species of Wild Flora and Fauna).

They are also being protected by YOU, when you share what you've learned about these unique turtles and inspire stewardship. Good Job!

9/16/11

LAP: Eastern Box Turtle, Part I

This is the first of two posts about the newest animal to be featured during a Live Animal Presentation at the New England Aquarium. Learn more about LAPs, or Live Animal Presentations, in this behind-the-scenes post.

Behold the Eastern Box Turtle (Terrapene carolina carolina), our newest LAP animal! 


Eastern box turtle. Photo courtesy National Park Service via Wikimedia Commons

This type of turtle is one of only two species of box turtles found in the US (the other is called ornate or western box turtle) and it is also the most common terrestrial turtle found in the eastern half of the US. Box turtles are unique for their highly specialized super-duper protective shell. The plastron has a hinge that can close up like a door so that its legs, tail, head and neck can be safely tucked inside out of a predator’s reach.


Photo courtesy Doug Letterman via Wikimedia Commons

Predators
Box turtle predators include skunks, raccoons, minks, dogs, snakes and rodents. Although these turtles have the unique hinged protection the population of predators is booming, increasing the chance of turtle predation. Predators such as raccoons, skunks, and rodents are benefiting from the availability of additional food sources such as garbage, bird seed and pet food.

Diet
Box turtles have a varied diet including insects, worms, slugs, lizards, berries, vegetable matter and carrion. They can even eat mushrooms that are toxic to humans. In fact, some folks have been poisoned by eating the flesh of box turtles that consumed toxic mushrooms. These turtles are also famous for their impact on the germination of the may-apple plant. May-apple seeds ingested by turtles have about a 38% germination rate, whereas un-digested seeds only have an 8.5% success rate. Box turtles, which are the may-apple’s main seed distributors, are able to reduce the thickness of the seed coat allowing germination to take place more easily. The may-apple root is being studied to use as a possible treatment for cancer.


Photo courtesy U.S. Fish and Wildlife via Wikimedia Commons

Habitats Box turtles are often found in forests, fields, thickets, marsh edges and bogs. When they’re feeling adventurous, they sometimes travel to shallow water at the edge of ponds and streams. In the heat of the summer, these turtles will wedge themselves into the soil surface to help retain moisture while they rest. In winter, box turtles hibernate in loose soil at a depth of about 2 feet, or sometimes under leaf litter, stump holes or mammal burrows. Box turtles have developed a tolerance for freezing similar to wood frogs, where the liver production of glucose acts like antifreeze. They are capable of surviving gradual partial freezing for a few days, but a sudden cold snap could kill them.


There much more to learn about the Eastern box turtle, like some of the challenges they're facing in the wild and what you can do to help them. Stay tuned for Part II of LAP: Eastern Box Turtle!

9/8/11

The Schooling Exhibit: You're Getting Sleepy...

As you approach the shiny, moving wall of herring that inhabit the Schooling Exhibit in the Aquarium's Thinking Gallery, you may quickly find that it's pretty difficult to focus on just one fish at a time. In fact, that's exactly the point. Take a look:

video

It's an effect that can be almost hypnotic to watch. Here's a frozen frame that makes it possible to pick out individual fish:



Groups of schooling fish, like the blueback herring in this exhibit, can coordinate their movements to make themselves look like one big, shimmering blur. This makes it very hard for predators to pick out one particular fish and attempt to chase it down. So, often, all a predator can do is just to swim into the group, mouth open, and hope for the best--not the most effective, or energy-efficient, of tactics.

The adaptations that make schooling behavior possible are very interesting, and almost amount to a special sixth sense for these fish. Check back soon to learn more.

-Tim