IELTS Reading Practice Test #25

The axolotl is a critically endangered amphibian native to a small series of lakes in the Valley of Mexico. Unlike most amphibians, which undergo a complete metamorphosis from larval to adult form, the axolotl (Ambystoma mexicanum) retains its larval features throughout its life, a condition known as neoteny. It keeps its external gills, finned tail, and aquatic lifestyle even after reaching sexual maturity. Growing up to 30 centimeters in length, it has a wide head, lidless eyes, and feathery gills that extend from either side of its neck. The axolotl’s skin varies in color, from dark grey to golden albino, depending on genetic variation. Though rare in the wild, it has become a model organism in scientific research due to its regenerative abilities and is often bred in laboratories and aquariums.

Axolotls are solitary and mostly active at night. They feed on small prey such as insects, worms, and tiny fish, using suction created by a sudden opening of the mouth. Their natural habitat consists of deep freshwater lakes with abundant vegetation, but their range is now restricted almost entirely to Lake Xochimilco, a remnant of a vast ancient lake system. Once common across central Mexico, axolotl populations have declined rapidly due to pollution, urban development, and the introduction of non-native predators like tilapia and carp, which compete for food and prey on axolotl eggs and larvae.

Although they can survive in captivity, axolotls have failed to reestablish viable wild populations despite multiple reintroduction efforts. The species does not breed easily in natural conditions, partly due to changing water quality and loss of critical breeding sites. Captive breeding programs have been operating since the mid-20th century, with the goal of maintaining genetic diversity and eventually restoring self-sustaining populations. These programs have supplied thousands of individuals for research, but few have been successfully released back into the wild.

The axolotl’s regenerative capacity has drawn major interest from scientists. It can regrow limbs, spinal cord, heart tissue, and even parts of its brain without scarring. Researchers hope that studying these processes might lead to medical advances in human tissue regeneration. However, this scientific interest has not translated into large-scale conservation outcomes for wild populations. Local and international conservation groups have launched habitat restoration projects and public awareness campaigns in recent years, though measurable success remains limited.

In 2006, the International Union for Conservation of Nature listed the axolotl as critically endangered in the wild. A 2013 study estimated that fewer than 100 individuals remained in natural habitats. In response, conservationists began building “axolotl shelters”—artificial channels protected from invasive species and pollution. These zones are monitored for temperature, oxygen levels, and aquatic plant coverage to simulate historical lake conditions. Community involvement has also become an essential part of conservation strategies. School programs, eco-tourism initiatives, and collaborations with local farmers are key to preserving what remains of the axolotl’s natural range.

Recent surveys suggest that small but stable pockets of axolotls persist in isolated areas of Lake Xochimilco. With continued habitat recovery, captive breeding, and active community engagement, experts believe there is still hope for the species’ survival. Conservationists emphasize that long-term success will depend on maintaining ecological balance in the region and ensuring consistent funding for restoration efforts.