Ethics review boards these days understand that potential outcry is proportional to the amount of empathy the public has for a specific type of animal. Even beyond the "potential outcry" angle, universities understand that such experiments threaten to reduce the public's ability to trust in the scientific process itself, which they rightfully recognize as an existential threat. I've taken the mandatory animal ethics course as a result of doing consulting work at a large research university, and it's clear that getting approval for an experiment involving any kind of primate is essentially impossible. Dogs and cats would be extremely difficult, random mammals like pigs and rabbits would be quite difficult, even arbitrary rodents would be non-trivial. As a result of seeking the path of least resistance, most experiments took place on flies, bees, worms, spiders, fish, mice, and the one specific breed of rat that is more-or-less automatically approved for all experiments (https://en.wikipedia.org/wiki/Laboratory_rat).