Category Archives: Crocodiles
A recently hatched Siamese crocodile at the Laos Zoo, part of an effort by the government of Lao PDR and the Wildlife Conservation Society to replenish the wild population of this critically endangered species. (Credit: M. Douangmyxay/WCS Laos Program)
ScienceDaily (Sep. 1, 2011) — Working with the government of Lao PDR, the Wildlife Conservation Society has helped to successfully hatch a clutch of 20 Siamese crocodiles, a species threatened across its range by hunting, habitat fragmentation and loss, and other factors.
The project is supported by the Savannakhet Province Agriculture and Forestry Office and MMG LXML Sepon.
“We’re thrilled at the prospect of augmenting the wild population of Siamese crocodiles with a new batch of healthy juveniles,” said Chris Hallam, Conservation Planning Advisor for the Wildlife Conservation Society’s Lao PDR Program and the crocodile project coordinator. “It’s a small but important step in helping to conserve a valuable part of the natural heritage of Lao PDR for the benefit of future generations.”
Launched in 2008 as the Crocodile Resource Management Plan, the project uses crocodile conservation as a means of protecting the larger landscape. The first phase of the project focused on surveys of crocodiles, the wetlands where they occur, and the livelihoods of local communities in Savannakhet Province. Survey teams located small numbers of crocodiles in several sites in the province’s river systems and wetlands.
The recently hatched eggs are part of the crocodile replenishment phase of the project, where eggs from wild nests are transported to captive settings in order to boost the survivorship of the clutches. The hatchlings will be released as second-year juveniles, when the reptiles are large and robust enough to avoid mortality in the wild.
The plan, say organizers, also relies on input and involvement from local communities, who will help promote the recovery of the Siamese crocodile and the habitat on which many livelihoods rely.
“This integrated project promotes the conservation of an entire landscape by highlighting the critical connections between an endangered species and local livelihoods,” said Joe Walston, Director of WCS’s Asia Program.
Classified as Critically Endangered by the International Union for Conservation of Nature, the Siamese crocodile grows up to 10 feet in length. The species has been eliminated from much of its former range through Southeast Asia and parts of Indonesia by overhunting and habitat degradation and loss.
Wildlife Conservation Society (2011, September 1). Rare Siamese crocodiles hatched in Lao PDR. ScienceDaily. Retrieved September 8, 2011, from http://www.sciencedaily.com/releases/2011/08/110830193857.htm
ScienceDaily (Oct. 8, 2009) — Alligators display the same loyalty to their mating partners as birds reveals a study published today in Molecular Ecology. The ten-year-study by scientists from the Savannah River Ecology Laboratory reveals that up to 70% of females chose to remain with their partner, often for many years.
The team, led by Drs. Travis Glenn, Ruth Elsey, Tracey Tuberville and Stacey Lance, spent a decade examining the mating system of alligators living in the Louisiana Department of Wildlife and Fisheries’ Rockefeller Wildlife Refuge (RWR) in Louisiana. Once they had successfully re-trapped a female they recognized the potential to examine individual behaviour over multiple mating seasons and determine if mate fidelity or pair bonding occurs.
“Given how incredibly open and dense the alligator population is at RWR we didn’t expect to find fidelity,” said Lance. “To actually find that 70% of our re-trapped females showed mate fidelity was really incredible. I don’t think any of us expected that the same pair of alligators that bred together in 1997 would still be breeding together in 2005 and may still be producing nests together to this day.”
This new discovery gives a new insight into the complex mating system of the alligator. Parental care is typically lacking in most reptiles, but not crocodilians who display parental care though nurturing young and defending the nest. In 2001 multiple paternity was discovered as the alligator mating system, yet it remains unknown as to how this benefits the species
However, while the females at RWR move freely through male territories, leading to high mate encounter rates, this study reveals that many alligators choose to mate with the same partner over many mating seasons. This amounts to the first evidence for partial mate fidelity in any crocodilian species and reveals a similarity in mating patterns between alligators and bird species.
Crocodilians are the sole surviving reptilian archosaurs, a group of ancient reptiles that includes dinosaurs and gave rise to birds. It is this evolutionary relationship to birds which means crocodilians are in a unique phylogenetic position to provide information about the ancestral mating systems of both birds and many dinosaurs.
“In this study, by combining molecular techniques with field studies we were able to figure something out about a species that we never would have known otherwise,” concludes Lance. “Hopefully future studies will also lead to some unexpected and equally fascinating results.”
- S.L. Lance, T.D. Tuberville, L. Dueck, C. Holz-schietinger, P.L. Trosclair III, R.M. Elsey, T.C. Glenn. Multi-year multiple paternity and mate fidelity in the American alligator, Alligator mississippiensis. Molecular Ecology, 2009