Bees may understand the concept of zero

https://www.newscientist.com/article/2142884-bees-are-first-insects-shown-to-understand-the-concept-of-zero/?utm_medium=SOC&utm_source=Facebook&fbclid=IwAR3t4Wj9o3fGtwHvN3C1hukqxJcjF29JWfwpzm6F2z4RqmNBEA07ZK9o2BI#Echobox=1552931157 via Bees are first insects shown to understand the concept of zero | New Scientist.