The amphibians of Los Árboles Tulum

The amphibians of Los Árboles Tulum

“OUR NOISY NEIGHBORS”

Written by Bac Yaroslab Becerril Vargas and Monica Maravert Solano. Translated by Denise Spaan

Los Arboles Tulum (LAT) is located within the Selva Maya, an area that spans from central Belize and Guatemala to the southeastern region of Mexico. Thanks to its size, it is considered the largest jungle in Mesoamerica and one of the most important globally. The biodiversity housed in these forests provide numerous ecosystem services that are beneficial for all the organisms that inhabit it, including humans. Some of these ecosystem services include the production of oxygen, maintenance of soil fertility, filtration of rainwater into the subsoil thereby refilling aquifers and connecting the terrestrial and aquatic systems (cenotes and underground rivers). In addition, the jungles of this region are a natural barrier against hurricanes and tropical storms that may cause flooding and destruction.

1.- Mapa de distribución de la selva Maya.  Imagen: www.googleearth.com


The Mayan Jungle is home to many species of plants, animals and other organisms. Among its trees, the chechén (Metopium brownei), chaká (Bursera simaruba), sapodilla (Manikara zapota) and ramón (Brosimum alicastrum) stand out among others. Animals such as spider monkeys (Ateles geoffroyi; Photo 2), coatis (Nasua narica) and the ornate hawk-eagle (Spizaetus ornatus; Photo 3) are just a few examples of the great biodiversity one can find in these forests.

2. “Diana” Hembra adulta de mono araña del grupo Cobá.
3.- Adulto de águila (Spizaetus ornatus) elegante en un nido (Foto: Cecilia Cahum Cahum).

In this jungle there are two well-marked seasons. The dry season lasts from October to May and the rainy season from June to September. During the wet season the plants turn green and many animals reappear after months of absence, such as some reptiles and amphibians. We will talk about the latter below: what are they and why are they threatened? What is its diversity, its importance and which species can we find in Los Arboles Tulum?

WHAT IS AN AMPHIBIAN?

Amphibians are a group of vertebrates, that is to say, they have a backbone and four limbs. The word “amphibian” comes from the Latin Anphi: Two, Bios: Life, which means “two lives”. This is due to the fact that half of their lives are carried out in the water and the other half on land (Photo 4).

4.- Ciclo de vida de un anfibio (Imagen: www.pinterest.com)


Amphibians go through processes of physical and physiological transformation during their lifetimes. Therefore, they are the only four-limbed vertebrates that carry out these drastic changes. Regardless of their life stage or appearance, amphibians rely heavily on fresh water.

This group of vertebrates has existed for 250-300 million years. They descend from an extinct group of animals, which were the first four-legged organisms (tetrapods) to leave the water to venture onto dry land (Photo 5). Currently there are about 7,500 species of amphibians that are grouped into three large orders.

5.- Tiktaalik (Tiktaalik roseae). Es el primer animal con columna vertebral y cuatro extremidades, en abandonar el agua y aventurarse en tierra firme. Imagen: www.amphibiianweb.com


The caecilians (Ghymnophiona) are the only amphibians that do not have legs, they are practically blind, deaf and prefer to spend most of their lives underground where the humidity is higher and sunlight is minimal. Caecilians look similar to earthworms (large earthworms). There are about 200 species and they feed on small arthropods and arachnids that live in the subsoil.

6.- Cecilia mexicana (Dermophis mexicanus) Foto: www.amphibianweb.com


Salamanders, axolotls and newts belong to the order of urodelos or caudates. This group of amphibians are lizard-shaped, however, it is easy to differentiate them from lizards as the urodeles do not have scales on their skin. Its immature or larval stage looks similar to their adult stage, with only minor differences between the two. Some species retain characteristics of immature individuals when they are adults. This group of amphibians are the only quadrupedal vertebrates that can regenerate limbs and internal organs.

7.- Axolote mexicano (Ambystoma mexicanum) Esta especie es “exclusiva” de los canales y lagos de la zona centro de México. Foto: www.amphibianweb.com

Frogs and toads are also known as “anurans or batrachians”. These amphibians undergo abrupt processes of metamorphosis. Their sizes vary from about 6 mm to 30 cm in length. Frogs and toads are the only amphibians that have the ability to emit vocalizations or sounds, to communicate with one another. Each species of frog of toad has an array of sounds exclusive to that particular species (Photo 8). These sounds are used to find a mate, define their territory, communicate the existence of water to other individuals of their species or as a persuasive mechanism against predators. Some species are also capable of producing toxins in their skin through special glands which help them defend themselves against predators (Photo 9).

8.- Rana arborícola mexicana (Smilisca dentata). Este adulto está inflando su garganta (saco gular) para emitir uno de los diferentes tipos de vocalización que esta especie utiliza para comunicarse. Foto: Gary Nafis
9.- Sapo del desierto de Sonora (Incilius alvarius) es un sapo que es capaz de producir una toxina en su piel de efectos psicoáctivos intensos. Foto: www.calphotos.barkeley.edu 

All three orders of amphibians are distributed throughout the world except for Antarctica and the Arctic Circle. Their diversity increases as we approach the equator, which is why the highest concentration of amphibian species is found in tropical countries where humidity levels are higher.

THE AMPHIBIAN CRISIS

Currently this group of vertebrates is one of the most threatened worldwide and it is estimated that several species of amphibians have disappeared from their natural habitats or have become extinct. This is caused directly and indirectly by human activities, in particular, the transformation, fragmentation, and degradation of amphibian environments. The increase in temperatures due to global warming causes the appearance of a fungus causing serious diseases in amphibians, and has resulted in the loss of many amphibian populations. This fungus is called Batrachochytrium dendrobatidis, or better known as amphibian chytrid fungus. Domestic pets such as dogs and cats like to prey on amphibians, forming another threat to their survival.

WHY ARE AMPHIBIANS IMPORTANT?

Amphibians play important roles in maintaining the health and functioning of the ecosystems they inhabit. For example, the presence of frogs and toads near a body of water indicates that has not suffered major contamination or deterioration. On the other hand, there are species that can live near sewage or places with high levels of human intervention, and as such are indicators of disturbed environments. In addition to being indicators of the ecosystem, frogs and toads also play fundamental roles in the food chain as both predators (Photo 10) and as prey (Photo 11).

10.- Rana de ojos rojos (Agalychnis tylori) alimentandose de un insecto. Foto: www.amphibianweb.com
11.- Serpiente períco alimentándose de huevos de rana arborícola. Foto: Christian Ziegler.

IN THE WORLD, IN MEXICO AND QUINTANA ROO


There are about 6,300 species of amphibians worldwide and Mexico is home to 376 species, thus being the fifth country in terms of diversity of these animals!!! Almost 50% of the species that exist in Mexico are endemic to this country, that is, they are not found anywhere else on the planet! The state of Quintana Roo is home to 14 species of amphibians: 1 salamander and 13 species of toads and frogs.

12.- Cecilias (Ghymnophiona) 2 especies en México. Fuente: Amphibia web.org
13.- Salamandras (caudata) 137 especies en México. Fuente Amphibia web.org

THE AMPHIBIANS OF LOS ARBOLES TULUM.

During the months of the wet season (May-September) you can observe and listen to the amphibians that inhabit LAT. In LAT we have observed 1 species of toad and 5 species of frog (see the table below for more details on the species). Surely you will have found or heard some of these animals hanging around your house and pool (mainly) at night.
Why do you find frogs and toads in your pool?


Amphibians look for your pool as a source to absorb water, feed on mosquitoes and other insects and from spring to summer they use it to spawn, laying eggs that over time will turn into thousands of tadpoles.
Is it dangerous for them to be in your pool?


The frogs and toads found in the LAT are not dangerous animals. The toxins that they may secrete from their skin are not harmful to humans, only to their prey. However, the pool can pose a danger to them as they may drown because the walls of the pools are usually very slippery, and as such they are unable to get out. Additionally, their permeable skin (which allows water to pass through its pores) absorbs the substances in your pool, such as chlorine, which can poison them. Therefore, we give you some suggestions if you do not want to see more frogs and toads in your pool and at the same time help take care of these interesting animals to maintain a healthy jungle:

  • You can cover your pool with a tarpaulin at night, thus preventing frogs and toads from entering the water
  • Turn off lights near your pool if you don’t use them. Light attracts insects which in turn attracts frogs and toads.
  • If you prefer not to cover your pool, you can put a board, branch, or rock at the edge of your pool leading into the water, serving as a ramp so that frogs and toads can get out again and don´t drown.

Living in the jungle is a wonderful experience but comes with great responsibility to care for the environment and all its inhabitants. Hopefully with these tips you continue to enjoy the jungle with all its noisy neighbors!

SPECIES YOU CAN FIND IN LOS ARBOLES TULUM

Common name in SpanishCommon name in EnglishScientific name
Sapo costeroGulf Coast toadIncilius valliceps
Rana arborícola mexicanaCommon Mexican tree frogSmilisca baudinii
Rana de ojos rojosRed-eyed tree frog or Taylor’s Leaf FrogAgalychnis taylori
Rana arbórea mahogany tree frog Tlalocohyla loquax
Rana lechera o rana marmoleadaMilky tree frogTrachycephalus vermiculatus
Rana espátula yucateca(this species is endemic and threatened with extinction)Yucatán shovel-headed tree frog, Yucatan casque-headed tree frog, or Yucatan casquehead tree frogTriprion petasatus