The Detroit Zoological Society (DZS) is excited to announce the successful breeding of the vulnerable Tokyo salamander (Hynobius tokyoensis). The Detroit Zoo is one of the only zoos in the world that has successfully captive bred this vulnerable species.

The Tokyo salamander is native to Japan, where a very limited population lives in temperate forests near freshwater springs; the water from the springs slowly oozes out onto the surface, keeping the ground moist. The number of Tokyo salamanders has been rapidly decreasing in recent years due mostly to habitat loss from residential and commercial development.

This breakthrough at the Detroit Zoo marks the beginnings of a potential assurance colony, a captive population that will hopefully help this species avoid extinction. With these new salamanders, the DZS team hopes to successfully establish assurance colonies in zoos that can someday augment or replenish declining wild populations.

In order to encourage Tokyo salamanders to breed, the environment has to be near perfect, and there’s no playbook to follow as little is known about Tokyo salamanders. The species is known to breed in temporary bodies of water, including paddy fields and ditches, which fluctuate in temperature and water level. DZS staff spent 2 years meticulously adapting indoor mesocosms in an attempt to replicate an environment prime for breeding.  Adaptations included simulating dry and wet “seasons,” natural temperature, light, humidity and water flow, which are parameters that can all have impacts on breeding success. In the Tokyo salamander, there is strong evidence that salamander sex ratios are also important for breeding success. By fine-tuning the environmental parameters, the DZS team was able to achieve success and looks forward to improving upon that success.

The Tokyo salamander is now well on its way to becoming another story in a long history of amphibian conservation work for the DZS. The DZS is committed to ensuring the survival of this species and many others. We will continue to learn about the Tokyo salamander and share our knowledge with others to help ensure that these incredible animals don’t become extinct.

By Dr. Ruth Marcec-Greaves, Detroit Zoological Society

Photo © Detroit Zoological Society