It&#x27;s usually found when looking within mammals and is only a first approximation at best, but it seems to be a useful one at least:<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Encephalization_quotient" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Encephalization_quotient</a>