Conservation and Natural History of the Titicaca Water Frog (Telmatobius culeus)
Conservation and Natural History of the Titicaca Water Frog, Telmatobius culeus
The Titicaca water frog (Telmatobius culeus) is one of the most unique species of frog in the world. Endemic to the Lake Titicaca and some of the surrounding lakes, there is little known about this species, resulting in a unique natural history. This species is considered the largest fully aquatic frog in the world, with a snout-vent length for males of around 120mm and around 138mm for females, and can weigh around 250 g (Knoll). Their coloration ranges from brown to greenish brown with white, black, or gray patterning. Males can be differentiated from females by the presence of nuptial pads on the males’ thumbs, which are thought to be used for gripping the female during amplexus (Muñoz-Saravia et al). It is important that people understand the natural history of this large aquatic frog and the conservation measures that are in place to preserve this species for future generations as to why it is unique. Specifically, the Titicaca water frog is unique because of its habitat and range, diet and reproduction, threats that they are facing, and the conservation programs in place to protect this species.
The first reason that this species is unique is its habitat and range. This species is endemic to Lake Titicaca and some of the surrounding lakes and rivers. The Titicaca water frog is completely aquatic and is found in depths between near the shore and 20m down. However, there has been evidence of them being found at around 120m (Knoll). These were most likely adults, since the juveniles are usually found in the shallows. T. culeus’s habitat is on the bottom of the lake but can vary between adults and juveniles. Studies have shown that adult frogs prefer a substrate of mud or sand with some rocks and diverse vegetation. Juveniles prefer a very rocky substrate, where the rocks are used as hiding spaces. Adults seem to avoid areas with lots of rocks, since surveys have found a smaller abundance of adults in these areas (Knoll). Another unique aspect of this species is their diet and reproduction.
The Titicaca water frog is also unique in its diet and reproduction. The diet of T. culeus has changed a little bit throughout the years. Sources written in 1922 recorded the stomach contents as aquatic insects, tadpoles of an unrecorded species, amphipods, snails, and occasionally fish (Allen). A later study in 2018 confirmed the original findings, and also added smaller T. culeus to the list of prey items (Knoll). This same study showed that T. culeus might not be an opportunistic feeder as was previously thought. While amphipods and snails were the most commonly found food source, they appeared to most commonly eat members of the genus Heleobia, one of the two genera of snails found, despite the other common species being equally abundant (Knoll). For the most part, this applied to adults more than juveniles, since the juveniles were found to eat the smaller and softer amphipods while adults moved up to the harder snails and even fish (Knoll). The Titicaca water frog is also unique in its reproduction. Unlike most amphibians that live in high altitudes, T. culeus is believed to have a year-long breeding season since eggs are found throughout the year in lower frequencies than would be found if they had a shorter breeding season (Knoll). This species lays fewer eggs then most species with a clutch size of 80-500 eggs. The eggs are laid in shallow water with the male remaining with the eggs until they hatch. Due to the cold temperatures in their environment, they have a longer tadpole stage than other frogs, lasting up to a year. Because of this they attain a large size after metamorphosing (Knoll). Despite how unique this species is, they are facing many challenges.
The Titicaca water frog is facing many challenges and issues in their home range. They are listed as critically endangered by the International Union for the Conservation of Nature (IUCN) due to several reasons. One main issue that they are facing is the emergence of chytridiomycosis, also called Bd. The first case of the fungal disease was recorded in 2015 (Knoll) and was reported as having a prevalence of 18.4% in wild specimens (Zevallos et al). While not much information about Bd in Titicaca water frogs exists, it is thought that the high pH and low temperatures of the lake make it challenging for the fungus to propagate (Berenguel et al). However, global warming may affect that by raising the water temperature, making it more suited for Bd. Another major issue that T. culeus is facing is humans collecting the frogs for both food and for traditional medicines. While it is not as common anymore, some restaurants around the lake serve frog meat collected from wild frogs. What is more common today is collecting for traditional medicines such as “extracto de rana” which is supposed to help with general health or “rana y maca” which is supposed have aphrodisiac properties (Knoll). Other problems that they are facing are rising water temperatures due to climate change and predation due to invasive species such as rainbow trout, which were introduced to the lake for fishing in 1939 (Knoll). There have also been several mass die offs in recent history for this species, with sudden changes in water quality being the suspect. So what can be done about these problems?
There are several conservation programs in place for Titicaca water frogs. One ex situ conservation project is captive breeding of this species. The K’ayra Center at the Museo de Historia Natural Alcide d’Orbigny and the Huachipa Zoo in Peru had the first success in captive breeding, and later frogs were sent to the Denver Zoo, who after successfully breeding them, sent them to several other zoos in the United States so that they could help with educating the public about them (Knoll). There are also some conservation projects going on at Lake Titicaca itself. One project is being done by some local women at the lake. They make small knitted frogs, frog beanies, and frog figure puppets to sell to the public, telling their customers about Titicaca water frogs and the problems they face (Fobar).They heard about the frog and the problems that they face from another in situ conservation project done by the Denver Zoo, where a biologist from the zoo gave a talk about T. culeus (Fobar). Personally, I think that there are several types of projects that we need to keep working on. One that zoos in the US are already doing is helping Bolivian and Peruvian conservation efforts by helping to construct breeding facilities and providing advice on husbandry. I also think that we need to focus on creating citizen science projects, because while there are already education opportunities in place in the cities around Lake Titicaca, I think we could get more people involved and interested with conserving this species by giving them an opportunity to see them in the wild and to help with collecting data on the frogs.
The Titicaca water frog is an incredibly unique species due to its habitat and range, its diet and reproduction, the threats that they are facing, and the conservation measures in place to protect this species. If we do not act now, we risk losing one of the most unique species of frog on the planet. In the current amphibian extinction crisis, we are at risk for losing many of our frogs. More research should be done for this species so that we can make better plans for long term conservation of this incredible South American species.
References
Allen, W. R. (1922). Notes on the Andean Frog, Telmatobius culeus, Copeia No. 108, 52-54. https://www.jstor.org/stable/1436304?seq=1#metadata_info_tab_contents
Barrionuevo, J. S. (2015). Skin structure variation in water frogs of the genus Telmatobius (Anura: Telmatobiiae). Salamandra 53(2), 183-192. https://ri.conicet.gov.ar/handle/11336/56717
Berenguel, R. A., Elias, R. K., Weaver, T. J., & Reading, R. P (2016). Chytrid fungus, Batrachochytrium dendrobatidis, in wild populations of the Lake Titicaca frog, Telmatobius culeus, in Peru. Journal of Wildlife Diseases, 52(4), 973-975. https://www.jwildlifedis.org/doi/full/10.7589/2016-01-007
Fobar, R. (2019). How poachers of this rare frog are now its protectors. National Geographic. https://www.nationalgeographic.com/animals/2019/04/former-peruvian-frog-poachers-help-protect-lake-titicaca-scrotum-frog/
Knoll, S (2017). Nutrition of the Titicaca Water Frog (Telmatobius culeus) [PDF file], Ghent University Facility of Veterinary Medicine. https://lib.ugent.be/fulltxt/RUG01/002/509/181/RUG01-002509181_2018_0001_AC.pdf
Reading, R.R., T.J. Weaver, J.R. Garcia, R. Elias Piperis, M.T. Herbert, C. Cortez, A. Muñoz, J.E. Rodríguez & Y. Matamoros (Eds.) (2011). Lake Titicaca’s frog (Telmatobius culeus) conservation strategy workshop final report [PDF file]. IUCN Conservation Breeding Specialist Group. http://www.amphibianark.org/wp-content/uploads/2018/08/Conservation-strategy-of-the-lake-titicaca-frog.pdf
Muñoz-Saravia, A., Callapa G., & Janssens, G. P. J (2018). Temperature Exposure and Possible Thermoregulation Strategies in the Titicaca water frog (Telmatobius culeus), Inter-Research, 37, 91-103. https://www.int-res.com/abstracts/esr/v37/p91-103/
Zellavos, S., Berenguel, R. A., Elias, R. K., Weaver, T. J., & Reading, R. P (2016). Batrachochytrium dendrobatidis in confiscated Telmatobius in Lima, Peru. Journal of Wildlife Diseases, 52(4), 949-952. https://www.jwildlifedis.org/doi/full/10.7589/2016-01-006
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