By Sebastian Wolf
In early 2016 Mitsinjo’s frog team brought several new, locally occurring frog species into the breeding facility, some of which had never been kept in captivity before.
After acclimatization we were curious when or if they would start breeding. Natural reproduction period of most local frogs starts with the first rains in December or January, yet the 2016-2017 season has been different due to the fact that rain was largely missing until now. Fortunately, Mitsinjo’s captive frogs did not care about this dry “wet season” as they continued to overwhelm us with eggs. All species in our facility except of one at least produced eggs and tadpoles and the first young tadpoles have successfully metamorphosed into froglets by now (sometimes incredibly tiny creatures like the one in the picture, an already 3 week old Platypelis barbouri which is roughly 4 mm in size).
There are two crucial issues in frog breeding: finding out which climatic and microhabitat conditions trigger reproduction, and caring for – often plenty – of froglets that need large quantities of small prey insects. Small changes in cage design (what scientists and zookeepers call structural enrichment) finally did the trick with Mitsinjo’s frogs and immediately resulted in egg-laying.
Having the world’s first captive bred animals of a certain species is exciting, yet not the end oft he effort. Aside from successfully raising froglets to mature individuals once, the next step should always be to breed the captive frogs into the next generation(s). This already worked out with our flagship species, the Golden Mantella where some of our second generation captive animals will soon be released at ponds within their natural distribution range. Among the species we bred for the first time were some elusive microhylids, a conspicuous bright-eye treefrog and a mantellid frog that has no free-swimming tadpole stage but where eggs develop into froglets inside the egg capsules – we call this the low-budget frog as it does not need to be fed during its larval stage.
Looking at the recent efforts raises our hope that we are capable of breeding other endemic species as well, in case of any emergency event that needs immediate rescue or mitigation action. Aside from husbandry experiments that we conduct to steadily improve care and maintenance protocols, the next big thing will be running breeding trials with more stream-breeding frogs as they are an important part of the frog fauna in rainforests here and can be quite demanding in some aspects.
Raising healthy frogs also requires vitamin and mineral supplements and proper food for tadpoles. Two companies thankfully provided free food and minerals for this breeding season (Aquarium Muenster and Keweloh Animal Health).