Animals nurture that partition of consciousness that they need to produce their own offspring. There is a certain parallelism between permanent consciousness, and the partition of it an animal needs to produce offspring.
"Proving Reincarnation with Quantum Physics" by No Apologies (6 min) has a woman explain how the quantum record of a mind can energize a developing baby about 5 weeks into pregnancy. You normally don't know what bodies used your life-experience set before. But having a 15 year old healthy body to start reusing the information of a physicist who might have lived to 100 sounds like a good deal. Does it matter how you die, as to the quality of the knowledge you pass on? Is a natural end much more likely to leave a closed record that a succeeding child can develop with? Unfinished music compositions (like Bruckner's Ninth Symphony, which he almost did complete) might exist in the quantum record, and another person might have access to it that way.