Neanderthal technology is thought to have been somewhat sophisticated, and include the Mousterian stone tool industry, the ability to create fire and build cave hearths, making the adhesive birch bark tar, crafting simple clothes similar to blankets and ponchos, seafaring through the Mediterranean, making use of medicinal plants and using various cooking techniques (such as roasting and smokin). Though they were likely apex predators, they still competed with cave bears, cave lions, cave hyaenas, and other large predators. Several examples of Upper Paleolithic art have been controversially attributed to Neanderthals–most famously Spanish cave paintings contentiously dated to before 65 kya and some claims of religious beliefs have been made. They were capable of speech, though it is unclear how complex their language would have been.
They likely lived in small groups, lacked sexual division of labour, and put children to work at a very young age. Neanderthals lived in a high-stress environment with high trauma rates, and about 80% died before the age of 40. They had a low population, leading to the accumulation of harmful genes and inbreeding. Interbreeding between Neanderthals and anatomically modern humans was concluded in the 2010 Neanderthal genome project's draft report, possibly occurring 316–219 kya and more likely occurring 100 kya and again after 65 kya. Around 1–4% of all non-Subsaharan African genomes (Eurasians, Oceanians, Native Americans, and North Africans) derive from Neanderthals, and about 20% of the Neanderthal genome survives today, but many of the inherited genes may have been detrimental and selected out.