The News
The News
Wednesday 06 of December 2023

Animals Next Door: Biodiversity in Mexico City

An axolotl in captivity from up close,photo: Wikimedia
An axolotl in captivity from up close,photo: Wikimedia
In Mexico City, some animal species have been able to maintain a healthy, stable population, while others find themselves facing the ever-present threat of extinction

People often forget, but humans are not the only creatures existing under the strain of life in Mexico City, with its loud noises, busy streets and smog clouds darkening the landscape under their gloom. Other animals live amongst us, in the inner city, around suburban areas and within the edges of the metropolis, where land remains untouched by the ever-expanding reach of human activity.

What follows is a list showcasing a few of the animal species that inhabit Mexico City. Some of them live all over the continent, while others exist exclusively in the Valley of Mexico or the capital itself. Some have been able to maintain a healthy, unthreatened population, yet others find themselves facing the ever present threat of extinction.

Mexican Plateau Horned Lizard (Phrynosoma orbiculare)

This species of lizard is easily differentiated from other by the rows of spines that run on the sides of its body, all the way to the flanks and top of the head, giving it the look of a medieval dragon or a prehistoric creature. It also goes by the names of Chihuahua Desert horned lizard, tapayaxin and, most interestingly, “blood weeper,” for its use of ocular auto-hemorrhaging (squirting blood from its eyes) to fend off predators.

With a body that rarely grows beyond nine centimeters (3.5 inches) long, the blood weeper usually inhabits forests and dry scrublands, although it might be found roaming agricultural land. Its natural habitat ranges from Mexico’s northern states and through the country’s central region, reaching towards part of the southwestern coast. Sightings in Mexico City occur mostly in the mountainside of the city’s southern edge, around San Miguel Ajusco and Pedregal.

A Mexican horned lizard being held as it bleeds from its eyes in an attempt to fend off danger. Photo: Wikimedia

The International Union for Conservation of Nature’s (IUCN) Red List labels the blood weeper under the category of Least Concern; its population remains stable and major threats to its wellbeing have yet to be identified. Nonetheless, the Mexican government has classified the species as Threatened under the Natural Resources and Environmental Secretariat’s (Semarnat) NOM-059-SEMARNAT-2010 norm. The blood weeper’s numbers have been lowered by deforestation, conversion of land for agricultural use and overcollecting for the local pet trade.

Two-Tailed Swallowtail (Papilio multicaudata)

A species of butterfly with a mythical connection. Locals call it xochiquétzal, a direct reference to the goddess of femininity, fertility and sexuality among the Nahuas, known for being a youthful temptress of mischievous nature.

The two-tailed swallowtail can be found pretty much all over the American continent: from British Columbia, Canada, United States and Mexico, all the way to Central America. It bears bright yellow wings with patterns of black stripes on the edges and traces of blue in its hind wings.

A two-tailed swallowtail with its wings in full display. Photo: Flickr

A relatively common sight throughout Mexico’s capital, xochiquétzals can be spotted mostly in the western and southern regions of the city, with a higher concentration in green areas like Chapultepec and Tlalpan Forest’s National Park.

The two-tailed swallowtail is not an endangered species, but researchers at the National Commission for Knowledge and Use of Biodiversity (Conabio) have wondered about the effects of human activity over its demographics and those of other species of butterfly native to the Valley of Mexico. They’re particularly concerned about the common practice of releasing swarms of butterflies during social events. Though the butterflies released are usually grown in captivity (mountain white butterflies, mostly), avoiding the need to capture specimens living in the wild, their sudden presence in natural habitats might upset the balance of native populations.

Chapultepec Splitfin (Girardinichthys viviparus)

An exclusive native to the Valley of Mexico, the Chapultepec splitfin is a small species of fish that tends to live in ponds, pools and small lakes. It has a minuscule, slim body: five centimeters (1.9 inches) of light brown colors and yellowish tones. During mating season, males turn brighter, while females acquire a darker hue.

This fish can be seen swimming in the city’s canals (Xico, Xochimilco and Tláhuac) and lakes (Chalco and Chapultepec). It might also be found in local markets, sold as dry fish for human consumption.

The Chapultepec splitfin is one of the area’s Critically Endangered species, according to IUCN’s Red List. The rapid growth of the city has dried and destroyed bodies of water where the splitfin used to live, fragmenting its population and isolating the existing colonies. Water pollution is also playing a role in the destruction of the splitfin and its habitat.

If it where to happen, the Chapultepec splitfin would not be the first species of fish to disappear in the Valley of Mexico. Three species of Mexican dace (Evarra bustamantei, Evarra eigenmanni and Evarra tlahuacensis) have been declared extinct in the last three decades.

Hyllus Beetle (Dynates hylus)

A mighty sight to behold, the hyllus is an armored tank among its fellow beetles. Its pale green husk and pincer-like horn make it both an astonishing and intimidating spectacle of a creature. Females, though hornless, keep the thick-armored body, usually colored in olive tones with patterns of black spots, giving them the look of a charred jewel.

A male hyllus beetle on display, seen from above. Photo: Wikimedia

The hyllus’s habitat ranges from the central and southern regions of Mexico through Central America. It’s larvae are commonly found in the trunks of avocado trees. In Mexico City, there have been sightings of them in the southern forests, near the mountainside.

Its population has not been declared as endangered by any sort of threat, yet the hunt of hyllus beetles for their beautiful husks, which are sold as jewelry in the black market, is a common practice.

Tláloc’s Leopard Frog (Lithobates tlaloci)

Another Critically Endangered species. For a while, the IUCN declared it extinct, being unable to find a single specimen since the mid 1980s; its webpage still describes the leopard frog’s population as “most likely extinct.” Nonetheless, the frog has been seen sporadically in the wetlands of Chalco and Xochimilco, south of Mexico City.

Tláloc’s leopard frog is native to the Valley of Mexico. It has a preference for wetlands, near bodies of water such as lakes. It is named after the Aztec god of rain, and also for its yellowish, almost golden skin and the irregular dark spots covering its body.

The city’s rapid expansion and use of potential habitats for housing and agricultural purposes remain major threats to this frog’s population.

Vermilion flycatcher (Pyrocephalus rubinus)

The vermilion fllycatcher is hard to miss. Its scarlet-feathered body and black wings pop anywhere it goes due to their contrast and beauty. It must be pointed out, though, that this particular color scheme is exclusive to adult males. Females and young males of the species bear a coat of faint brown with a faded spot of orange igniting near their belly.

As its name suggests, the flycatcher feeds on insects: from flies and grasshoppers, to beetles and butterflies. It will launch at its prey to catch it in mid-air, sometimes diving straight at it to pick it up from the ground.

A vermilion flycatcher perched on a wire in São Paulo, Brazil. Photo: Wikimedia

The vermilion flycatcher is a fairly common species on the American continent. It inhabits the southwestern United States, Mexico, Central and South America. It can live pretty much anywhere as long as there’s open space and bugs to feed on. In Mexico City, the flycatcher can be seen roaming near the southern mountains, around Pedregal and the National Autonomous University of Mexico (UNAM) campus, with small flocks seen in the inner city’s greener areas, like Condesa and Chapultepec. It can also be found sporadically in Tlanepantla and regions of the far north.

Cardinal meadowhawk (Sympetrum illotum)

One of the 43 species of dragonfly in the city. The cardinal meadowhawk is a tiny, reddish dragonfly of about four centimeters (1.57 inches) long. It lives in much of North and Central America, inhabiting small bodies of water, like ponds, lakes and even fountains. Sightings in Mexico City occur frequently in Pedregal and the lakes and fountains of Chapultepec.

A cardinal meadowhawk eating while perched on a pipe. Photo: Wikimedia

There’s no sign of the meadowhawk’s population being threatened in Mexico City. Nevertheless, there’s no record of their presence in heavily polluted bodies of water, such as the Mixcoac and Magdalena rivers. This means water pollution could render some of the meadowhawk’s preferred habitats inhabitable.

Pedregal tarantula (Aphonopelma anitahoffmannae)

Fact: Mexico holds the second largest number of tarantula species in the world (93), beaten only by Brazil. The Pedregal tarantula is one of two species of tarantula native to Mexico City and its surroundings, the other being the Hemirrhagus chilango, or the chilango tarantula.

Pedregal tarantulas live for the most part in the forests, ravines and scrubland around Pedregal, Ajusco, Milpa Alta and Los Dinamos Ecological Park. They also have a fondness for underground caves, which makes them quite vulnerable to land excavation. In addition to the threat of displacement by city growth, Pedregal tarantulas are occasionally captured to be sold as pets.

To this day, there’s no conservation program in places to protect the species from habitat loss.

Mexican salamander (Ambystoma mexicanum)  

The world famous axolotl. Recognized for the strangeness of its branch-like gills and the childish nature of its face, this species of salamander is an icon of the oddities to be found in the animal kingdom.

Axolotls live in the lakes, wetlands and canals of Chalco and Xochimilco, south of Mexico City. They require deep-water lakes and abundant vegetation for nesting. Due to the specificity of their needs, axolotls suffer greatly from urbanization and water pollution. They’re also sold in markets as pets, food and medicine, reducing their numbers even further. For this very reason, the IUCN has labeled axolotl as a Critically Endangered species.

A pair of axolotls on display at the Vancouver Aquarium in British Columbia, Canada. Photo: Wikimedia

Fortunately, the Mexican government has recognized the urgency of the situation and declared the species under Special Protection by the country’s environmental laws. Also, there have been attempts to increase its numbers in the wild. In 2015, Semarnat released 500 formerly captive axolotls into Xochimilco’s canals in hopes of giving a boost to the species’ population.

Volcano rabbit (Romerolagus diazi)

A tightly-packed ball of fur with short, upright ears and a barely visible tail, the volcano rabbit is a perfect example of tenderness in nature menaced by external forces that ignore its vulnerability.

The second smallest rabbit in the world — first place goes to the pigmy rabbit — volcano rabbits, known locally as zacatuches, live in pine forests near volcanic areas. In Mexico City they can be found roaming around the Popocatépetl and Iztaccíhuatl volcanoes.

The IUCN has listed the species as Endangered. Over-exploitation of pine forests, overgrazing and man-made fires have destroyed and fragmented the volcano rabbit’s habitat. Captive colonies exist in Chapultepec, yet infant mortality among them is quite high. Also, laws meant to prohibit its hunting are poorly enforced.