If we consider the huge number of fossil remains of ice age mammals dredged up from the floor of the North Sea, we can only conclude that the Pleistocene era must have resembled a paradise between what is now the UK and the Netherlands. The majority of the remains date from the late Pleistocene (somewhere between 100,000 and 10,000 years ago), and we are speaking of TONS of bones, mammoth molars, tusks, hooves, teeth, and so on. These are the remains of large grazers, especially the mammoths. It appears that the area between the UK and Holland was not the North Sea we know today. Rather, it was a huge, mostly treeless, dry steppe, where the Thames from the West and the Rhine, Meuse and Schelde from the East meandered into river deltas before entering the Atlantic Ocean way to the North. This was the typical landscape at that time, the megafauna steppe, found stretching across the land masses of the Northern Hemisphere in which the mammoths, rhinos, steppe bison and their associated, large predators were thriving.
The enormous amounts of mammoth remains in the North Sea suggest that large herds of these pachyderms roamed the area: in terms of a larger time frame, think of hundreds of thousands of animals. The most abundant remains are molars, due to their hardness and durability. The abundance of the last molars, the M3/m3, also reveals that animals were attaining advanced ages, suggesting good health and, therefore, suggests the presence of good environmental conditions. Nevertheless, remains of juvenile animals are also a common phenomenon.
Unfortunately, complete skeletons have never been found in the North Sea. Sometimes, matching fossils are found in the nets of the fishermen when they dredge the sea floor for flatfish. For instance, the upper and lower jaw of the same individual may be found together. This indicates that the animal must have lived and died in that area instead of being transported there over a great distance from the mainland to the sea by rivers or ice sheets.