Complex sentence: However, as its habitat increasingly disappeared, meat consisted of only 40% of its dietary intake in the late Middle Ages, until modern times where meat now makes up little more than 10--15% of its diet.
Split into simpler sentences: However, as its habitat increasingly diminished, the portion of meat in its diet decreased with it until by the late Middle Ages, meat consisted of only 40% of its dietary intake. Today, meat makes up little more than 10--15% of its diet.