Elephants
It's well known that elephants have great memories. When a human harms or kills one of their herd members, they may attack poachers or villages.
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Chimpanzees
Chimpanzees are extremely clever primates that are capable of harboring resentment and acting aggressively toward people who have harmed them in the past.
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Dolphins
Dolphins may exhibit aggression. There are reports of them intimidating or even killing sharks, which some people think might be retaliation for earlier injuries the sharks caused.
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Crows
These perceptive birds are able to identify faces. They can remember a human who has intimidated or harassed them and launch attacks at that individual.
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Camels
Camels are sometimes unyielding. They could turn hostile and try to bite or kick their handlers if they are mistreated.
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Whales
Anecdotal information implies that whales may remember and retaliate against vessels that have collided with them, even if this has not been thoroughly documented.
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Komodo Dragons
These big reptiles can smell rather well. They may seek out and try to kill their attacker if they are hurt by a person or animal.
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Scorpions
Certain species of scorpions can perform a "sting dance" in response to threat, repeatedly stinging the ground or any item they believe to be a threat—though this behavior isn't strictly revenge-seeking.
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