Galapagos Giant Tortoise Health
Galapagos Giant Tortoise Health
The drivers of movement strategies – food availability, reproduction and competition – interact with physiology and environment to determine in turn the health status of tortoises.
Since 2013, the team veterinarians try to visit each tagged tortoise for their annual health checks. During these visits, the tortoises get a visual physical exam, body measurements and weight are recorded, and blood, swabs, and fecal samples are collected. Blood samples are analyzed for baseline blood parameters to help determine an individual’s overall health. Ultrasound technology determines the presence of follicles and/or eggs to assess the reproductive status of females. This health information is integrated with the movement data to help us better understand how migration affects the health and reproduction of individuals.
Various research studies have been conducted for turtles and tortoises to evaluate how incubation temperatures affect the sex of the developing tortoise. We also examined that question as part of the giant tortoise health studies, examining temperatures at different nest sites and ground elevations.
Starting in 2013, we fitted hatchling tortoises with small radio tags, weighing only five grams, that allowed us to track the baby tortoises to evaluate tortoise survival and growth over time.
Due to the dedicated work of our team as well as support from many others, many of our research questions have been answered. These findings were shared and discussed with local management institutions such as the Galapagos National Park Directorate, Ministry of Agriculture, and Galapagos Biosecurity Agency, among others.
The Galapagos Tortoise Movement Ecology Program (GTMEP) team members and collaborators published numerous papers about the variety of questions answered by our research, and they all had strong conservation implications.
By 2017 it was clear that the conservation implications of tortoise-human interactions remained an enormous challenge for management and protection of these iconic animals. In response to this unsolved challenge, new areas of research were identified, all of which related to One Health and conservation.
You will find many (many!) definitions of One Health but at its core, the concept recognizes that animal, human, and environmental health are all connected and understands that the health of any one affects the health of the other two.
A new research study was started in 2017 as part of Dr. Nieto Claudin’s PhD dissertation. This study involves the detection of pathogens and antibiotic resistance in Galapagos tortoises as a way to determine how human activities such as farming, use of antibiotics, pollution, and waste management may affect tortoise health, and ultimately, the health of its ecosystems.
The health component of the GTMEP has numerous goals including identification of disease threats to the endangered Galapagos tortoise and determination of the effect of human encroachment including livestock, agriculture, and roads into the tortoises’ natural habitats.
In 2015, we were able to study the different methods used to determine white blood cell (WBC) numbers in Galapagos tortoises. It is hard to believe, but unlike humans and a few animals, such as dogs, cats or horses, in which the methods to measure the number and types of WBCs is well known, there remains much to be discovered for tortoise hematology work.
Through our studies, we have published the best method for determining this important health parameter in Galapagos tortoises. For more information, see “Comparison of total leukocyte quantification methods in free-living Galapagos tortoises (Chelonoidis spp.).”
In 2017, we conducted a pilot study on 30 tortoises from western Santa Cruz Islands. Samples were collected from each tortoise to assess the overall health of the tortoises and test our methodologies.
In 2018, Kathleen Apakupakul, the molecular biologist with the Saint Louis Zoo Institute for Conservation Medicine, traveled to the Galapagos to establish a mobile molecular lab with Dr. Ainoa Nieto Claudin.
While some samples are sent back to the U.S. for testing, Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) restrictions require an extensive permitting process to import tissue from endangered species outside of the home country.
Establishing a mobile lab in the Galapagos obviates the hassle and logistics of exporting samples and provides teaching opportunities for local scientists. The experience setting up the mobile molecular lab in the Galapagos can also be transferred to establishing local labs at other field sites to build capacity in conservation areas of concern.
More than 600 tortoises from four islands and eight species have been sampled and tested for diseases.
The molecular lab uses a process called polymerase chain reaction, or PCR, to identify pathogen DNA on the tortoise swabs and determine if an individual tortoise was infected. All swab samples are tested to determine whether tortoises that live close to humans are more prone to infection than those that live in relative isolation from human activity.
By 2020, more than 600 tortoises from four islands and eight species have been sampled and tested for diseases including adenovirus, herpesvirus, ranavirus, and mycoplasma. Also, 300 tortoises from Santa Cruz and Alcedo have been tested for antibiotic resistant bacteria.
Read about the first ever detection of antimicrobial resistant genes on Galapagos giant tortoises from Santa Cruz in “Antimicrobial resistance genes present in the faecal microbiota of free‐living galapagos tortoises (Chelonoidis porteri).”
These health assessments will help us to gain a better understanding of both current and future issues that may impact not only the health of the giant tortoises, but also the well-being of all inhabitants, animal and human, of the Galapagos Islands.