Face the Facts: Marmoset Experiments at UMass

  • Drills holes into the skulls of tiny marmoset monkeys1
  • Threads electrode leads down through their abdomens1
  • Zip-ties them into restraining devices2
  • Surgically removes the females’ ovaries3
  • Deprives them of fluids to coerce them into cooperating4
  • Administers hormone-manipulating drugs3,5
  • Separates them from their cagemates in order to cause stress6,7
  • Holds hand warmers against their bodies to simulate hot flashes3
  • Uses male monkeys as a control group1,3
  • Then kills them.8

Learn more about the deadly experiments here.


1Gervais NJ, Viechweg SS, Mong JA, Lacreuse A. The middle-aged ovariectomized marmoset (Callithrix jacchus) as a model of menopausal symptoms: Preliminary evidence. Neuroscience. 2016;337:1-8. doi:10.1016/j.neuroscience.2016.08.056

2Nephew BC, Febo M, Cali R, et al. Robustness of sex-differences in functional connectivity over time in middle-aged marmosets. Sci Rep. 2020;10(1):16647. doi:10.1038/s41598-020-73811-9.

3Gervais NJ, Remage-Healey L, Starrett JR, Pollak DJ, Mong JA, Lacreuse A. Adverse Effects of Aromatase Inhibition on the Brain and Behavior in a Nonhuman Primate. J Neurosci. 2019;39(5):918-928. doi:10.1523/JNEUROSCI.0353-18.2018

4Workman KP, Healey B, Carlotto A, Lacreuse A. One-year change in cognitive flexibility and fine motor function in middle-aged male and female marmosets (Callithrix jacchus). Am J Primatol. 2019;81(2):e22924. doi:10.1002/ajp.22924

5LaClair M, Lacreuse A. Reversal learning in gonadectomized marmosets with and without hormone replacement: are males more sensitive to punishment? Anim Cogn. 2016;19(3):619-630. doi:10.1007/s10071-016-0966-5

6Rothwell ES, Workman KP, Wang D, Lacreuse A. Sex differences in cognitive aging: a 4-year longitudinal study in marmosets. Neurobiol Aging. 2022;109:88-99. doi:10.1016/j.neurobiolaging.2021.09.015

7Vaughan E, Le A, Casey M, Workman KP, Lacreuse A. Baseline cortisol levels and social behavior differ as a function of handedness in marmosets (Callithrix jacchus). Am J Primatol. 2019;81(9):e23057. doi:10.1002/ajp.23057

8Edwards M, Lam S, Ranjan R, Pereira M, Babbitt C, Lacreuse A. Letrozole treatment alters hippocampal gene expression in common marmosets (Callithrix jacchus). Horm Behav. 2023;147:105281. doi:10.1016/j.yhbeh.2022.105281

Get PETA Updates

Stay up to date on the latest vegan trends and get breaking animal rights news delivered straight to your inbox!

By submitting this form, you are agreeing to our collection, storage, use, and disclosure of your personal info in accordance with our privacy policy as well as to receiving e-mails from us.

 Ingrid E. Newkirk

“Almost all of us grew up eating meat, wearing leather, and going to circuses and zoos. We never considered the impact of these actions on the animals involved. For whatever reason, you are now asking the question: Why should animals have rights?” READ MORE

— Ingrid E. Newkirk, PETA President and co-author of Animalkind