Role of predators overrated

One would expect that on all islands, baby deer safely grow up into adulthood without much trouble, far away from warm-blooded carnassial danger. On islands, with their typically unbalanced faunas, large and medium-sized terrestrial carnivores are entirely missing. This creates a safe, perhaps even arcadian environment. Not so. We found for a fossil population of endemic deer (Candiacervus, Crete, Late Pleistocene) an unexpectedly high juvenile mortality, similar to that reported for extant mainland ruminants. Age profiles show that deer surviving past the fawn stage were relatively long-lived for ruminants, indicating that high juvenile mortality was not an expression of their living a "fast" life. The Sicilian dwarf elephant (Palaeoloxodon falconeri) was shown to have lived a "fast" life, which means a short life, lots of offspring of which many don't make it (Raia et al. 2003). This is not the case for Candiacervus. Juvenile mortality for Candiacervus was caused by diseases, accidents (Crete is mountaineous), starvation and so on, just as on the mainland or perhaps even more so. What does this message tell us? We think that precisely this high juvenile mortality acts as a great selective tool, permitting rapid adaptation to the new environment, and in the case of Candiacervus, radiation and speciation. Without this selective filtering, such processes likely could not take place so fast: 6 or 8 species in at most 125 thousand years. Read the article at

New data on the Late Pleistocene Cretan deer Candiacervus sp. II

For our museum, we mounted a skeleton of the endemic Late Pleistocene Cretan deer Candiacervus sp. II (Liko Cave), using bones of different individuals. This composite skeleton contributes to the study of taxonomy of insular ungulates as it reveals some additional features that were not detected in the isolated elements. Candiacervus sp. II differs from all known recent and extinct mainland deer, mainly in its proportions. Although its considerably shortened distal limbs were already noted in the past, Candiacervus sp. II now appears at the same time to have had a more or less normal vertebral column length relative to continental large deer, and moderately upwards curved lumbar section, both features reminding us more of the insular dwarf bovid Myotragus than of the mainland small deer Axis axis. Combined with an increased massivity of all bones and pronounced muscle scars, this change in body proportions appears to indicate that Candiacervus sp. II evolved towards the niche of goat-like bovids in rocky environments. Other additional diagnostic features are the horizontally directed transversal processus of the vertebras, fusion of the lateral metacarpal to the main metacarpal, a tail length of ten vertebras, a more pronounced difference between anterior and posterior hooves, and the presence of lateral toes upto the third phalanx, anterior as well as posterior.

Read more in VAN DER GEER A.A.E., DE VOS J., LYRAS G.A., DERMITZAKIS M.D. (2006). New data on the Pleistocene Cretan deer Candiacervus sp. II (Mammalia, Cervinae). Courier Forschungsinstitut Senckenberg 256: 131-137. For a pdf, send an e-mail to geeraae@geol.uoa.gr. For more Candiacervus publications, visit our websites at http://users.uoa.gr/~geeraae and http://users.uoa.gr/~glyras

For more general info on the extinct Cretan deer, see http://en.wikipedia.org/wiki/Candiacervus

Crete before the Cretans: the reign of dwarfs

Crete was completely submerged during the Pliocene, and gradually emerged in the Early Pleistocene. New and empty islands like these are normally colonized overseas by sweepstake dispersal, which means that only a limited number of taxa is able to reach the island. This results in an unbalanced mammal fauna, as a rule consisting of only elephants, hippopotamus, deer, cattle, rodents, insectivores and sometimes otters. After successful colonization, as a rule a fast evolutionary change takes place, which can be explained as an adaptation to the restricted island environment. As a result, island faunas are very different from mainland faunas, but similar to each other. Crete is no exception to this general pattern, and during the Pleistocene there were two successive endemic mammalian faunas. The first (the Kritimys-biozone) is characterised by a dwarf mammoth, a dwarf hippopotamus and a giant mouse. The second (the Mus-biozone) is characterised by a dwarf elephant, a dwarf deer (next to medium and large-sized deer) and a large mouse. The reason for the dramatic faunal turnover between the two biozones is unknown, but may very well have been related to a significant sea-level drop. This decreases the distance between the now larger island and another firm ground. The second fauna got extinct just before or after the arrival of the first humans. Problems of dating and the lack of paleolithic artefacts or human remains obscures this point. In any case the fauna of the second biozone was already completely extinct at Aceramic Neolithic and Minoan times, and replaced by newcomers who came together or along with the humans.

Read more in VAN DER GEER A.A.E., DERMITZAKIS M., DE VOS J. (2006). Crete before the Cretans: the reign of dwarfs. Pharos 13: 121-132. Netherlands Institute at Athens, Greece. Free pdf [ 2,197 kb] at http://users.uoa.gr/~geeraae/publications/2006-pharos-crete.pdf .