Do animals get jealous like people? Researchers say it's complicated

Using data from 23 studies of what psychologists call ‘inequity aversion,’ researchers combed through results of more than 60,000 observations involving 18 animal species. In what they said was the ‘largest empirical investigation of non-human inequity aversion to date,’ the team reconstructed data analyses and used a new metric that adds depth to the concept of fairness.
Read more: Do animals get jealous like people? Researchers say it's complicated