I think this is the only evidence of a non-human species conducting complex funerary practices.

https://en.wikipedia.org/wiki/Homo_naledi

Homo naledi is an extinct species of archaic human discovered in 2013 in the Rising Star Cave, Cradle of Humankind, South Africa dating to the Middle Pleistocene 335,000–236,000 years ago. The initial discovery comprises 1,550 specimens, representing 737 different elements, and at least 15 different individuals. Despite this exceptionally high number of specimens, their classification with other Homo species remains unclear.

H. naledi anatomy indicates that, though they were capable of long-distance travel with a humanlike stride and gait, they were more arboreal than other Homo, better adapted to climbing and suspensory behaviour in trees than endurance running. Tooth anatomy suggests consumption of gritty foods covered in particulates such as dust or dirt. Though they have not been associated with stone tools or any indication of material culture, they appear to have been dextrous enough to produce and handle tools, and likely manufactured Early or Middle Stone Age industries. It has also been controversially postulated that these individuals were given funerary rites, and were carried into and placed in the chamber. In December 2022, suggestions that H. naledi used fire for light and cooking were reported.