Posts Tagged ‘Tortoises’

Our Tortoises Get More Room

Posted by in Dr Joe's Giant Tortoise Adventure,Endangered,Reptiles

Do you ever visit our tortoises here at the Houston Zoo? They are so cool and prehistoric looking.  It’s fascinating to see how they operate with what looks like a heavy shell and limited range of motion. But they can move pretty fast if they want to.

We’ve just expanded the tortoise habitat from the Duck Lake sidewalk near the Dolly’s Ride sculpture all the way around toward the food court. We’ve installed new grass and almost doubled their area. They move faster than you would think. Why don’t you stop by?

There are three kinds of Tortoises who live together there – Radiated tortoises, Galapagos tortoises and African spurred tortoises.  Let’s talk about the latter. The African spurred tortoise, Centrochelys (Geochelone sulcata), is a large tortoise found along the southern perimeter of the Sahara desert in Africa. It is the largest species of tortoise found in Africa and is surpassed only in size by the Galapagos tortoise and the Aldabra tortoise.

The African spurred tortoise

The species gets its name from several large prominent spurs that are located on the hind surfaces of the thighs on the rear legs. Males can be distinguished from females by having a pronounced concavity on the underside of their shells and by their larger tails. Adult males also are larger than females and can reach weights of up to 180 pounds, while females rarely get above 100 pounds.

Diet and Reproduction: In terms of diet, Spurred tortoises are largely herbivorous and will accept a wide variety of fruits and vegetables. At the zoo, they can often be seen grazing on the grass inside their enclosure. These animals are prolific diggers, and can dig burrows of over ten feet long. In the wild, Spurred tortoises breed between November and May and can lay on average anywhere from 13 to over 30 eggs.

The eggs take around 120 days to hatch and the young weigh around 50 grams each. Like other turtle and tortoise species, the Spurred tortoise exhibits what is called “TSD” or Temperature Sex Determination. The sex of an individual is determined not by sex chromosomes, but by the incubation temperature of the egg. Learn more about TSD!

Lifespan: African spurred tortoises can live a long time! Captive longevities of over a century have been reported, and there currently are a number of captive animals that are over 50 years old. Our animals at the zoo were acquired as young adults in 1988. Because of their long lifespan, the Spurred tortoise figures prominently in many animal legends among the native tribes occupying its home range.

The Galapagos tortoise

Spurred tortoises as pets: Spurred tortoises breed readily in captivity and hatchlings are often seen for sale in local pet shops. However, there are several things to consider before purchasing one:

1. Size. This species will grow to a large size very quickly, and adults are very powerful. They have been known to overturn central air conditioning units, and to dig extensive burrows underneath houses which can undermine the foundation. Spurred tortoises need a very large, secure area to roam and they also require an indoor area with heat when temperatures drop below 50° F.

2. Longevity: If properly cared for, there is a very good chance that the Spurred tortoise purchased will outlive the person who bought it in the first place. If you are buying a tortoise for a child, think about what you will do with the animal when the child grows up and goes away to college. A long-term plan is needed for keeping this species (note: the zoo does not accept Spurred tortoises as donations; we already have all we need).

3. Diet: These animals need proper nutrition in order to have normal shell growth. There are many captive turtles that have shell malformations due to poor diets. Even though they will eat a variety of different fruits and vegetables, the portions and the types have to be carefully monitored.

4. Lighting: Proper lighting also contributes to proper shell growth. Inadequate lighting also will result in shell deformities. Spurred tortoises need ample exposure to unfiltered sunlight.  When kept inside, they need special heat lamps that provide the necessary light wavelengths.

The World Chelonian Trust also provides useful information on caring for Spurred tortoises. Visit their website http://www.chelonia.org/articles/sulcatacare.htm if you’d like to learn more.

The Radiated tortoise

Please come and see our African spurred tortoises, along with Radiated tortoises and our Galapagos tortoises on your next visit and write us to let us know what you think.

Don’t miss a special evening with a  Galapagos tortoise researcher on December 9, 2011. Our Call of the Wild Speaker Series will feature Dr. Stephen Blake from the Max Planck Institute of Ornithology with a special introduction from Dr. Joe Flanagan, Director of Veterinary Services, Houston Zoo. Event begins at 7:00 p.m. Drinks and hors d’oerves will be served. CLICK HERE for tickets and information!

If you’d like to read about the Galapagos tortoise, click HERE to read our Dr. Joe’s blog series about his adventure to the Galapagos Islands and how he helped several Giant Tortoises!

Written by Stan Mayes, Herpetology

Dr.Joe’s Giant Tortoise Adventure: Last Day on Pinta

Posted by in Animal Info,Birds,Conservation,Dr Joe's Giant Tortoise Adventure,Endangered,Reptiles,Tortoise,Uncategorized

May 19, Wednesday, Pinta Island 

This morning will be our last on Pinta. I was able to climb up to the tortoise area relatively early and  spent time enjoying the scenery, watching tortoises moving through the vegetation, eating, sniffing, and looking around. I also enjoyed watching the guardaparques work as they carried tortoises up the hill, passing the tortoises to the next team at each transition point. Generally, there was no evident loss of momentum anywhere along the route. I watched a few arrive, then followed a trail of a tortoise a few hundred meters up the hill. While watching her, I heard a lot of cheering and suddenly worried that I might be missing “the arrival” of the last tortoise. I hurried back, painfully beating through vegetation that had not been opened by a tortoise yet. I got back to find my fears were for naught.  There were still a few more tortoises to arrive. The smallest tortoise came up on the back of one of the crew members from the Sierra Negra. The captain was extremely gracious in allowing his crew to help with this project. Normally the vessels used here are worked by a crew that focus entirely on the duties of maintaining the vessel. While this crew left nothing to lack with respect to their ship duties, they were also so excited about the release that they did whatever they could to participate. It was one of the crew who was able to heft the smallest tortoise (20 kg, or 44 lbs) onto his shoulder and walk the entire 4 km himself! 

The Guards gather around the last tortoise, number 39

The next tortoise was number 39! He arrived and the entire string of guardaparques were there to meet him. A lot of cheers, back slapping, hand shaking, smiles, and laughter went on for quite some time. The tortoise, oblivious to the din, sat in the grass and started to eat within about 2 minutes of hitting the ground. We then all took photos to document this historic event, and began to work our way back to shore. Along the way down I enjoyed the beauty of the habitat. The mixture of ecosystems, plant communities, and diversity of wildlife along the way. Near shore, a Galapagos hawk nest was perched in a prickly pear tree. An adult peered over the side of the nest as if to say “stay back” and others were circling in the area. Doves flew by. This is an incredibly beautiful, peaceful place. 

A Galapagos hawk surveys the activites.

Back at the beach, the people who had started the tortoises on their ascent today had done a little beach clean up. Although the Galapagos are 600 miles from the nearest land, marine debris and trash regularly washes ashore. When in these remote areas, if possible, people working for the park will do what they can to de-litter all the accessible areas. It’s a wonderful and important service. 

The afternoon was restful. The students were getting their last direct contact that they would have with people for 10 weeks. While there’s a chance that they’ll get a mid-term visit to check supplies, there are no guarantees — only if time permits.  The sea lions came back and there seemed to be more of them.  After dinner, we said our good-bye’s to the students and they got into the panga, and were dropped on the beach.  The ship pulled anchor and we headed out of harbor.  As the ship went into motion, swallow tailed gulls started following along. This is the only nocturnal species of gull in the world, and 1 of 2 gull species endemic to Galapagos. They are very likely the most beautiful gull in the world.  They are easily seen in several of the tourist visiting sites, sometimes on nests with eggs or young.  It was a wonderful treat to get to see them fly alongside the boat. I finally decided to try to capture an image using my camera on an “open” setting with flash. It seems to have worked, but the white dot is not necessarily National Geographic quality! Sleeping was pretty easy that night. The boat in motion was more stable, and everyone was exhausted from all the work on Pinta. 

We pulled into port at 6:oo a.m. Thursday morning, right on schedule. 

That might be the final day on Pinta Island, but now that Dr. Flanagan is back in Santa Cruz, there’s much to do. Come back to read the next installment. 

Written by Dr. Joe Flanagan