A. mexicanum’s life cycle is rather special, since this species exhibits neoteny, which means that it retains its larval form into adulthood and becomes fertile without going through metamorphosis (Clare 2015). In the laboratory, it is possible to induce the metamorphosis by injecting thyroxin, but the metamorphosis is lethal for the organism (Khattak et al. 2014). The life of A. mexicanum is divided in five stages. As with every amphibian, the life of A. mexicanum starts as an egg, surrounded by a jelly substance. Stage 2 is an embryo just before the hatching. The axolotl becomes a young larva, still without limbs in stage 3. Their limbs will start to develop in stage 4. The axolotl’s age is now about 2 weeks. The front legs take form first, and afterwards its hind legs will develop. In the fifth and final stage A. mexicanum becomes sexually mature. It takes about two years for A. mexicanum to attain its full size (Clare 2015). Healthy axolotls can reach ages of more than ten years (Gresens 2004). A. mexicanum reproduces sexually. Reaching sexual maturity depends on environmental conditions, but it should be between five months and two years. A female can …show more content…
mexicanum has a very small habitat and is endemic to Mexico. It is only known for living in a small area near Mexico-City (see figure 2) When A. mexicanum was discovered, it lived in two lakes underneath Mexico City, namely Lake Xochimilco and Lake Chalco (Zambrano and al. 2010). At present time, there is not much left from Lake Chalco, since it is almost drained. Lake Xochimilco is also reduced in size due to less flooding (Lake Xochimilco 2015). On top of that, the lakes are polluted by Mexico-City. The disappearance of big parts of these lakes and their pollution has caused the population of A. mexicanum to decline. Moreover, A. mexicanum is eaten by local people (Zambrano and al. 2010). Altogether this has made A. mexicanum a critically endangered species on “The IUCN Red List of Endangered