Axolotl

Intro: 00:05

Welcome to Bad at Goodbyes.

On today’s show we consider the Axolotl.

Species Information: 02:05

The Axolotl is a critically endangered amphibian native to southern North America, in Mexico, Mexico City.

Adults can range in size from 6 to 18 inches in length, with an average size of 9 inches. Their bodies are cylindrical and elongated, with a broad, flat head. Wild axolotls are typically a mottled brown or black color with gold speckles.

One of their most distinctive features is the three pairs of feathery external gills stalks that protrude from the sides of their head. These gills allow them to breathe underwater while their underdeveloped lungs, which are also functional, allow them to take occasional gulps of air at the surface.

They have barely visible vestigial teeth. The primary method of feeding is by suction.

They have four short, underdeveloped legs with four toes on their front feet and five toes on their hind feet; these digits are long and thin. Their tail is long and narrow with a fin that extends from behind their head to the tip of that tail. This is an anatomy built for speed and when threatened, the axolotl can swim up to 10 miles per hour.

The axolotl has a highly specialized adaptation: it does not heal by scarring and is capable of the regeneration of entire lost appendages regrowing limbs in a matter of months. And can even regenerate more complex structures, such as parts of their central nervous system, and tissues of the eye and heart and brain.

Axolotls have relatively simple eyes compared to other animals. They do not have eyelids, meaning their eyes are constantly exposed, making them sensitive to light and primarily adapted for detecting movement and changes in light intensity rather than forming sharp images.

Instead they rely on other senses, like their lateral line system which is a network, common to many salamander, of specialized sense receptors along their head and body, that is highly attuned to vibration, specifically water movement; they can sense changes in water currents. Their lateral line receptors also can perceive low-frequency sound. And sense the weak electrical fields generated by other organisms.

And so, between their eyes, ears, sense of smell and lateral line system, the Axolotl is able to navigate, hunt, communicate, mate, and escape predation in the dim murkiest waters of its habitat.

The axolotl is native only to the freshwater of Lake Xochimilco and and previously Lake Chalco both in Mexico City. Lake Chalco no longer exists, having been drained as a flood control measure over the first 70 years or so of the 20th century.

Lake Xochimilco persists, but only as a remnant of its ancient self, existing mainly as canals and a few developed and urbanized bodies of water in the middle of the Parque Ecológico de Xochimilco which includes playgrounds, soccer fields and spaces for wedding receptions.

Summer temps in their habit average in the low 80s °F and winter lows in the mid 40s °F. The region experiences moderate annual rainfall, averaging around 27 inches, with the majority falling between June and October.

The region is historically characterized by chinampas, an ancient agricultural technique that involved interweaving reeds and mud to create artificial islands, raised beds of fertile soil, floating gardens used to cultivate crops. They were first constructed at Xochimilco at least 600 years ago. This land has been shaped by our species for a long time.

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In the dream, I visit. New York to Mexico City, and in the dream, because it is a dream, I am there suddenly, without the long journey and any of the trifling complexities that keep us apart. Our days together are unworried, talking and cooking small meals, we stoll revolucion, we sing in the evenings, we walk in the park. We walk in Parque Xochimilco, never knowing how close we were, how close we are, to something so precious. In the dream.

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The actual lake bed Xochimilco is primarily composed of volcanic rock and sediment, with varying depths and a mix of submerged vegetation and open water areas that support aquatic plants, like: Water lilies, Elodea, Duckweed, and common Reeds and Rushes. As well as fauna like frog and heron and squirrel and snail and egret and fish like the Charales and the Mexclapique, alongside introduced species like tilapia and carp. A variety of invertebrates: insects, crustaceans, and mollusks live in and near the waters.

Axolotls are carnivorous and their diet mainly consists of small invertebrates, like mosquito larvae, water fleas and brine shrimp; Mollusks like snail and small clams; and small fish.

Axolotls are ambush predators, meaning they lie in wait for their prey rather than actively chasing it. They use their specialized senses to detect, and their suction feeding, to capture their prey. Once detected, they create a suction force that draws the prey into their mouth along with water. Their mouths are lined with small, backward-facing teeth that help prevent the prey from escaping. So after capturing the prey, they close their mouths and swallow it whole. They cannot chew, so they rely on digestive enzymes to break down the food in their stomachs.

They typically hunt at night when their prey is more active. They are opportunistic feeders and will consume any available food within their size range.

Axolotls are solitary and do not exhibit complex social structures. However, they do coexist peacefully in groups as long as there's enough space and food. While occasional interspecies interactions occur, they are brief and mainly related to courtship and mating.

During breeding season, axolotls use pheromones to attract mates and communicate. During courtship, males perform a dance by vigorously fanning their tail to waft pheromones towards the prospective female. And females have been observed performing subtle body movements that seem to indicate receptivity. The male then deposits small, cone-shaped packets of sperm on the bottom of the lake. The female intakes that sperm into her reproductive organ and her eggs are fertilized internally.

Within 1-3 days after mating, the female lays hundreds of eggs, attaching them to aquatic plants or other lake bottom surfaces. The eggs hatch within two to three weeks, and the young, though vulnerable, are capable of surviving on their own. They primarily absorb their yolk sacs and develop their external gills, starting to swim and explore their environment. After a few days, they will begin to actively seek food and will gradually start to develop their limbs. By around 6-8 weeks of age, they will resemble miniature versions of adult axolotls. They reach reproductive adulthood after about one year.

Most amphibian begin their lives as aquatic animals, unable to live on dry land: tadpoles. To reach adulthood, they go through metamorphosis, in which they lose their gills and leave the water, generally only returning to breed. Axolotl are unusual, they rarely metamorphose, retain certain larval characteristics, including keeping their gills into their reproductive adulthood and live their entire lives underwater.

The estimated average lifespan of the axolotl is 6 years.

Human encroachment, due to development and urbanization has substantially shrunk the axolotls native habitat.

And what remains is threatened by multiple stressors. Pollution, stemming from agricultural runoff and untreated wastewater, has degraded water quality. The introduction of non-native species, the tilapia and carp, has disrupted the ecosystem, creating new competition for resources and the larger fish prey upon axolotl eggs and larvae.

The small size of the wild population has also resulted in a loss of genetic diversity, a genetic bottleneck, that makes the species more susceptible to disease and less adaptable to environmental changes, such as the effects of human induced climate change.

The axolotl is protected by the Mexican government, who prohibit the capture, possession, or trade of wild axolotls without proper permits.

Conservation efforts are focused on captive breeding programs, habitat restoration, and public awareness campaigns. Researchers are also exploring the potential of reintroducing captive-bred individuals into suitable habitats, both within and outside of Lake Xochimilco, a strategy called translocation.

tically endangered species in: 2020

t is estimated that less than: 1000

Citations: 20:01

IUCN – https://www.iucnredlist.org/species/1095/53947343

San Diego Zoo - https://animals.sandiegozoo.org/animals/axolotl

Animal Diversity Web at the University of Michigan – https://animaldiversity.org/accounts/Ambystoma_mexicanum/

Wikipedia – https://en.wikipedia.org/wiki/Axolotl

Music: 21:29

Pledge: 32:12

I honor the lifeforce of the Axolotl. I will endeavor to hold its name, a seed of awe and remembrance, gently on my lips. I am grateful to have shared time on our small bright planet with this amazing little being. I lament the ways in which I and my species have harmed and diminished this species.

And so, in the name of the Axolotl I pledge to reduce my consumption. And my carbon footprint. And curb my wastefulness. I pledge to acknowledge and attempt to address the costs of my actions and inactions. And I pledge to resist the harm of any kin or their habitat, by corporations and governments.

I pledge my song to the witness and memory of all life, to a broad celebration of biodiversity, and to the total liberation of all beings.

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