Long buffalo joke

In a municipal ranch, there once lived a family of buffalo. There was a baby male buffalo (around 10 years old or so), a daddy buffalo and a mommy buffalo. The baby buffalo attended the local elementary school and the parents were respected members of the neighborhood and both had pretty decent jobs, but life was still rough and at times the family found themselves barely scraping by, sometimes not even. Now, as the buffalo family lived in a rough neighborhood, drugs were very common and the parents, during a period of mental distress, were introduced to heroin by one of their friends. At first it was a casual thing, they'd shoot maybe once a week or so to take the edge off, but over time what was once a weekend vice spiraled into crippling addiction, and it got to the point where they both lost their jobs, and would do anything they could to support their fix, and this meant sometimes selling their son for sex. When the son protested, the parents would beat him, but in places where people couldn't see, such as the back, stomach and legs. The parents would often resort to beating the baby buffalo whenever anything happened that upset them, regardless of how irrational or little the present issue had to do with their son. After about 4 months of this behavior, one of the baby buffalo's teachers noticed him limping and wincing in pain every time he moved, so she inquired and upon finding out about the situation, called Child Protective Services. CPS launches an investigation and (miraculously..) are able to jail the parents and they tell the child that he will be placed in foster care. In the last fleeting moments that all three are under the same roof, as the parents are being dragged past their child and out of the house, they find themselves confused, realizing all they have done. Finding themselves near speechless, they struggle to mutter their last words to their child:
"Bison"