BREEDING EMYS ORBICULARIS IN CAPTIVITY (The European Pond Turtle)

Andy C. Highfield

The European Pond turtle (or terrapin) has a wide distribution throughout continental Europe and North Africa. There is fossil evidence that its range once included Great Britain, Sweden, Denmark, the Netherlands and Estonia, but it has long been extinct in these regions due to climatic change.

Today, it is found in freshwater ponds and streams in France, Italy, Spain, Southern Germany, Poland, Romania, Bulgaria, Turkey, Iran and the Balkan states among other places. A comprehensive list of localities would be very extensive, as this turtle can be found from Spain to Morocco taking in most of the Mediterranean coastline en route.  In some localities, practically every habitable pond has its resident orbicularis.  This apparent abundance is deceptive, however, as in many parts of its range populations show evidence of severe decline. Changing agricultural practices in particular have been identified as a major contributing factor in this decline. In Southern France and Italy the rate of decline is particularly acute. The replacement of drainage ditch earthen sides with concrete, and the regular burning of surrounding vegetation are especially damaging, not only to E. orbicularis but also to other reptiles and amphibians which share similar habitat preferences. In northern parts of their range, Emys orbicularis hibernate for several months over winter, while in hot, southern regions they aestivate to avoid the extreme heat. 

Taxonomy

The classification of Emys orbicularis is in something of a state of flux, with 13 subspecies in five subspecies groups having been described or resurrected in recent years. It is clear that marked regional differences in size, colouration and marking occur. At present, there is much debate as to the validity of these various races or subspecies. From a practical point of view, until this is resolved, the best advice to keepers is to maintain groups from known localities separately, and to breed only from those that closely match each other in physical characteristics.

Reproductive behaviour

Sexual activity in captive E. orbicularis is reported to begin in nature at 3 to 4 years of age, although captive examples mature much earlier.  The breeding season in the wild extends from early spring until May or June, with marked regional variations. Courtship is usually initiated by a frontal approach, followed by the male biting the face and neck of the female. Finally, copulation occurs. Oviposition (nesting) typically follows within 4 to 6 weeks. Most nesting occurs in June or July, though it may be earlier in some localities. The number of eggs appears to depend upon the size of the female; typically, 3-5 eggs are laid, though as many as 16 have been reported.  The eggs are elliptical, with soft, pliable and leathery shells. The females maintained by the author lay an average of 4 eggs per clutch, and may nest twice per year. Nests are usually excavated in loose, peaty soil, and often among the roots of plants.

An adult basks under a UV-Heat lamp

Incubation and hatchling care

The eggs of E. orbicularis are reported to be highly reliant upon TSD, or Temperature Determined Sex. At temperatures of 24-28 C, only males are produced, but at a temperature of 30 C 96% of hatchlings are female. We have not had the opportunity to verify this, as all of our hatchlings to date have resulted from nests that were not incubated in a controlled environment. The females simply nested in the land area of their pond which is situated in a covered greenhouse. The eggs incubated there, quite successfully, at ambient temperatures, which ranged from extremes of 16 C to 32 C. In one instance, we were not even aware of the existence of the nest until we spotted what appeared to be a large beetle wandering around the enclosure! The “beetle” turned out to be a freshly hatched Emys orbicularis. Since then, our group on European pond turtles has bred regularly and our first generation are now beginning to engage in mating behaviour of their own, so a second generation success with this species may not be too far off.

A captive-bred juvenile reared by the author

Environment

Both adults and juveniles do well in surface-mounted ponds, or in standard pre-formed ponds sunk into and earthen substrate. For juvenile ponds, we find a submerged Fluval 4 canister filter is quite adequate to ensure good water quality, particularly when an airstone and air pump is also added to boost oxygen levels and to help prevent stagnation. A basking spot is mandatory, and we have found that the self-ballasted mercury vapour lamps such as the UV-Heat range are ideal for use with this species. Emys orbicularis are very susceptible to calcium and D3 deficiency problems, so anything that promotes D3 synthesis is welcome. The water in the indoor ponds is changed every 2-3 weeks, and this also appears to promote reproductive activity almost immediately in response.

Two hatchlings

Diet

Emys orbicularis are omnivorous, with juveniles initially feeding upon insect larvae and small earthworms. We have also observed our juveniles to feed upon floating duckweed and other aquatic plants. We provide our standard aquatic turtle fare of mixed Reptomin sticks, rehydrated dried trout chow, rehydrated low fat dried cat food (in limited quantities) and free access to floating pond plants or salad. We dust all dried foods prior to hydration with a phosphorus-free calcium and D3 supplement, and also regularly provide chunks of cuttlefish bone for the turtles to gnaw upon. This they do with great relish, and using this regime, no developmental problems have been noted. Shell development is smooth and even. 

In summary, Emys orbicularis are a highly attractive and interesting turtle, which appears to possess quite a high degree of intelligence. It is certainly very adept at exploiting any opportunity to escape, so good security is important. They are particularly skilful at climbing vertical surfaces. When maintained in good quality, secure environments, however, they are fascinating to watch, and captive breeding may occur with very little artificial intervention required!

(c) 2002-2003 Tortoise Trust