Succeeding the Eemian or the Last Interglacial, the Last Glacial period (115, 000 -11, 000 years ago) began. It is a well known fact, that during this time, cave bears (Ursus ex. gr spelaeus) were widespread in Eurasia. This lineage was closely related to recent brown and polar bears. Althought rivaling their extant relatives in terms of dimensions (and on average being heavier), cave bears were specialized herbivores. It can be deduced from numerous factors (isotope analysis, tooth microwear…). There is no doubt they would be a formidable adversary when confronted with our ancestors.
Cave bears (Ursus ex. gr spelaeus) were very diverse, with different forms living on different localities and having different prefences (altitude and perhaps also plant types..). In central and eastern Europe, Ursus ingressus was one of the largest forms, occupying habitats below the ranges of the smaller, high alpine subspecies such as Ursus spelaeus ladinicus and Ursus spelaeus eremus.
As it has been found, U. ingressus and U. s. eremus were living sympatrically for 15,000 years in Austria, with no apparent interbreeding. This is an evidence, that they must have niche partitioned and were quite different ecologically.
There were also a lot of different forms. For example, the classical Ursus spelaeus spelaeus was found in western Europe.
The brown bears (Ursus arctos) lived alongside cave bears, but were more carnivorous than they are today. This was to avoid competition.
Literature used:
- Explanations from Prof. Martin Sabol, PhD.