The March bi-annual health assessment for Dermatemys mawii began on Saturday, March 5, and will wrap up on Tuesday, March 8, 2022. This is the first health assessment since March 2020 that we’ve been able to invite participants from abroad.

The Hicatee Conservation and Research Center has experienced successful breeding of our captive population of turtles since 2014. Since then, hundreds of turtles have been hatched at the facility. However, because there is little research on the species to date, we have not been able to distinguish male hatchlings from female hatchlings. To ensure a successful re-wilding program, we must verify the ratio of males to females. And, if the ratios are not correct, then we will use that information to modify our incubation methods. This health assessment is dedicated to determining our sex ratios at the HCRC.

Research shows that if a turtle’s eggs incubate below 81.86 Fahrenheit, the turtle hatchlings will be male. If the eggs incubate above 87.8° Fahrenheit, however, the hatchlings will be female. Temperatures that fluctuate between the two extremes will produce a mix of male and female baby turtles.

Turtle biologist, Dave Rostal, and Veterinarians, Elliott Jacobson and Isabelle Paquet-Durand are performing endoscopies to determine the sex of our hatchlings. Simultaneously, Bryan Windmiller and Emilie Wilder from Zoo New England are taking morphometric photos of each turtle to see if their plastron shape can help determine the sex of the turtles.

We are also collecting typical growth data on a subset of turtles as well as reviewing their overall health and performing ultrasounds on adult females.

Participants: Zoo New England Staff: Bryan Windmiller and Emilie Wilder; Visiting Veterinarian: Elliott Jacobson, Professor Emeritus, University of Florida, Visiting Biologist: Dave Rostal, Southern Georgia University, Local Veterinarian: Isabelle Paquet-Durand, Visiting Volunteers: Doris Dimmitt, Rod Dimmit, Emily Gregory, Tim Gregory, and Alexi Dart-Padover, BFREE staff: Thomas Pop, Jonathan Dubon, Mark Canti, Elmer Tzalam, Jacob Marlin, and Heather Barrett. BFREE Team Hicatee chef: Edwardo Pop.

Thanks to Zoo New England for their support of this health assessment as well as for their ongoing support for the program.

by Thomas Pop and Jonathan Dubon

Last year, HCRC Manager, Thomas Pop, and Wildlife Fellow, Jonathan Dubon, separately witnessed two amazing events during their daily work at the Hicatee Conservation and Research Center. Tom observed captive Dermatemys mawii (Hicatee turtle) exhibiting courtship behavior and mating and later Jonathan recorded a female Hicatee laying eggs. Both events were firsts for the staff of the HCRC. Tom and Jonathan describe their individual sightings below.

Tom’s Account of D. mawii mating:  

During the 3-4^th week of October 2021, I observed the following events:

Searching: I noticed that several males were following a single female and thought it might have been to initiate a courtship ritual. I saw the males searching both in the mornings and in the evenings on some days. This caught my attention because Hicatee rarely come to the surface of the water and generally only poke their nostrils out to breathe. I did not see any females searching for a male partner to mate with, but we cannot discard this idea as we do not have enough evidence.

Pre-copulation: Several activities were noted before copulation during this time. I saw that the males would try to get behind the female as if they were trying to pick up on a scent or hormone. The male turtles would then try to bite the female’s tail, as well as her marginal scutes and face. Males were observed shaking their heads from side to side while in front of the female, thereafter, trying to bite the female’s face. Again, I witnessed these activities sometimes in the mornings and evenings. There has not been any evidence of individuals being territorial or aggressive towards each other at the HCRC, including male to male, until this recent observation. The only aggression noticed was between dominant males and a female that may have been ready to mate.

Copulation: I noticed that one of the male turtles would try to jump onto the female turtle when they were a little deeper in the water and hook on. The female would then walk into the shallow water around the edge, so the male’s carapace was out of the water a bit.  I used this time to take some photos and videos. I also noticed that before mating, the male would try to drag the female a little deeper into the water as opposed to the shallow edge. Being that this activity happened around the edge of the pond, the turtles made the water very murky by disturbing the dirt present. During this time, I only observed the mating twice. I also noticed that the female involved in the copulation did not seem to want to go deeper in the water. She somewhat preferred to stay around the edge of the pond and seemed stressed.

Jonathan’s account of D. mawii laying eggs:

On December 22^nd, 2021, around 7:30 am, I opened the gate to the HCRC and checked around the breeding ponds for nests that might have been deposited overnight. I was stopped in my tracks when I noticed a female Hicatee on land, digging a nest hole with her hind legs. I stood still and remained quiet so as not scare the turtle. She also remained still, and after about a minute or two, she continued to clear out the nest hole. I carefully snuck up behind her and took out my phone to document the occasion. 

At first, I was stooping down but my knees started to ache, so I sat down. After a little while, I laid down a few feet behind her so that I could get some great angles of the event. She continued to remove dirt from the nest hole for 15-20 more minutes. She then laid the first of a total six (6) eggs at around 8:05 am. I noticed that she would place one of her hind legs in the hole when she was laying, to hold and gently lower the egg into the hole. After placing the egg down, she would use her hind legs, switching between the two, to move the egg around and gently set it in place. She repeated these actions in the same way for all six eggs. By 8:30 am, approximately 25 minutes later, she was finished laying. 

After setting the final egg in place, she then began to pull dirt with her hind legs from around the hole to cover it. It took her around seven minutes to cover the nest with dirt while slightly compacting it. After covering up the nest, she slowly turned around and made her way back into the water, at the 8:37 am mark. 

To my surprise, she did not seem bothered by my presence. I do know that some sea turtles allow you to observe and even touch them while they are laying eggs, but I was not sure if Hicatee turtles would do the same. I did not want to risk scaring her, so I played it safe and tried to remain invisible and quiet throughout the activity. 

Why these observations are important:

BFREE Executive Director, Jacob Marlin, was very impressed by the incredible observation and documentation skills of Tom and Jonathan. He stated, “The documentation of courtship, breeding and nesting demonstrates one of the many benefits of developing the HCRC. This species has very secretive habits and barely comes out of the water, even to nest. These events have never been documented in the wild and without the Hicatee Conservation and Research Center and its dedicated staff, this incredible behavior would likely continue to elude science.”

Watch a short video of the events described by Tom and Jonathan at the HCRC.

About the Hicatee Conservation and Research Center:

BFREE is home to the Hicatee Conservation and Research Center (HCRC), a captive breeding facility for the Central American River Turtle, Dermatemys mawii, locally known in Belize as the Hicatee. The Hicatee is classified as Critically Endangered by the IUCN Red List and is listed in the report, “Turtles in Trouble:  The World’s 25 Most Endangered Tortoises and Freshwater Turtles – 2018,” by the Turtle Conservation Coalition. The HCRC was established along with the support of the Turtle Survival Alliance in 2011. Over the last ten years, the team has grown to include several additional partners working together to study reproductive biology, nesting ecology, and the feasibility of breeding Hicatee in captivity. To learn more about BFREE’s work in protecting the Hicatee, visit www.bfreebz.org/research/#hicatee

Photography and Videos by Thomas Pop and Jonathan Dubon. Video compilation by Jonathan Dubon.