It was the gekoes that killed them because of the DDT
Cats
The Geckos ate the flies that were sprayed with DDT. The cats ate the geckos that were dead and dying from eating the poisoned flies. Then cats started dying which allowed the rats to proliferate which allowed the spread of Bubonic Plague.
Lack of suitable food !
Defenive
Cats are carnivores by nature and normally prefer fish on top of the food chain, however, they will also eat grass if not feeling well.
Geckos are not at the top of the food chain. They are at the bottom.
The geckos were full of poison
It makes fun of actions by a government.
In "Top of the Food Chain," the cats primarily ate the rats that they caught. They were skilled hunters, able to catch their prey and feed themselves in the absence of their owners.
It would probably be the birds, if they are eating the grasses. Fleas eat the blood of the birds and cats, the cats eat the birds.
In "Top of the Food Chain" by T. Coraghessan Boyle, the townspeople ask the questions that the speaker responds to. They are curious and concerned about the strange occurrences happening in their town.
A domestic cat is just below a dog in the food chain. However, in the wild, big cats are generally at the top.