About 10 million years ago, towards the end of the Miocene period, the fourth episode of the Alpine movements threw up the Maltese Islands area above sea-water, thus exposing the region to the forces of denudation and allowing for the colonisation of the exposed land by plants and animals by a process of simple sea/wind dispersion. A major change in the Islands' area occurred about 6.5 million years ago, when the closure of the Gibraltar straits sealed off the Mediterranean from the Atlantic allowing the former to dry out significantly so that the subterranean ridge (which includes the Maltese Islands) was completely exposed connecting the Islands to mainland Europe and probably Africa. This connection facilitated the liberal exchange of continental plants and animals, a situation that persisted until about 5 million years ago when tectonic activity opened the Gibraltar straits allowing the Mediterranean to refill thus isolating the Maltese Islands from the mainland. The Maltese Islands are situated on a shallow submarine ridge which connects with the Ragusa peninsula of Sicily. This ridge would be fully exposed by a sea-level drop of 100-120 m.

About 2 million years ago, the world climate underwent a series of cold-warm periods which gave rise to the Ice Ages. These climate fluctuations caused the periodic growth of ice sheets on land in high latitudes and mountains during the glacial periods, while the interglacial climate was similar to those prevailing today. The ice cap during the glacial periods advanced at a rate of 100 m/yr. and has been estimated to have been about 2500 m thick across Europe. The ice cap however never reached further than 400 latitude and thus the Maltese Islands were never covered with ice. The regions south to 40^o latitude were affected by Pluvial periods which saw very unsettled weather with increasing rain precipitation. The Mediterreanean region may in fact have been rather arid during the glacials, increasing in humidity during the interglacial periods. The cool wetter climate of the Pluvial period allowed the southern extension of the Central European forests of pine, olive, juniper, cedar and fir. In addition the uptake of water in the increasing ice-cap resulted in a drop in the sea level, estimated at a total drop of 150 m in the Central Mediterranean during the last Ice Age. This sea level drop was sufficient to expose the submarine ridge of the Central Mediterranean thus connecting the Maltese Islands to mainland Europe. The advancing cold weather in Europe also forced the warm-loving animals to migrate southwards reaching the Maltese Islands. It is estimated that the Pleistocene period may have undergone a total of about 17 cold periods. This cycle of mainland connection of the Maltese Islands followed by a period of isolation allowed for the development of a number of endemic species which were generally characterised by dwarfism of the herbivore mammals and gigantism of rodent, reptilian and avian species. Similar species development has also been reported from other Mediterranean small islands.

During the Late Middle Pleistocene (c.130,000-180,000 years ago), the excavated fauna clearly suggest a wetter climate than that prevalent today. There is also evidence of a small lake in the west of Malta. However the presence of Laurel suggests a Mediterranean climate characterised by a hot dry season. The animals prevalent during this period included the dwarfed endemic hippopotamus and elephant species, besides extinct species of dormice, bats and avian remains. The deposits are generally referred to as Hippopotamus or Leithia cartei layer. No human remains or artefacts have been definitely associated with this stratigraphical layer.

The mainland connection was again re-established during the last Ice Age period during Late Upper Pleistocene (23,000 - 10,000 years ago). During this phase the climate in the Central Mediterranean was cooler than that prevailing today. A large number of species have been excavated from the various Late Upper Pleistocene deposits on the Maltese Islands, the prevalent animals appear to have been stunted forms of deer (Cervus elaphus), scanty remains of small sized carnivores (Ursus, vulpes, canis), and remains of bats, voles, birds, turtles and amphibians. Deposits of this period are typically referred to as Cervus or Pitymys melitensis layer. Stratification studies of trenches dug at Ghar Dalam suggest that the Cervus layer frequently had incorporated hippopotami and elephant remains in the lower layers, in association with Carnivores and Cervus. Human remains and artefacts were also found in this stratigraphical layer. The uppermost layer of the Cervus horizon was apparently devoid of carnivores and pacchyderms.

The recurrent land-links between the Maltese Islands and Sicily resulted in similar faunal associations in both regions. The Pleistocene Sicilian faunal repertiore have been grouped into four main stages dated by various techniques. Several Maltese faunal associations have been described from various sites in Malta - the most important sites being Ghar Dalam and the Maghlaq Region with its caves and costal deposits. An attempt has been made to correlate the Maltese faunal associations with those reported in Sicily.