# Rat Universes

An episode of [The LRB Podcast](https://invisiblenetwork.ai/podcast/510327102), 23 Jul 2025, 44 min.

Audio: https://www.podtrac.com/pts/redirect.mp3/traffic.megaphone.fm/LRB9503987634.mp3?updated=1754562326

The first true lab rat was the Wistar rat, a strain specifically bred for biomedical research. In his “rat universe” experiments, John B. Calhoun placed large numbers of these rats in a controlled environment for more than a year, and found evidence for the same anxieties sparked by their urban cousins: overpopulation and an ensuing ‘behavioural sink’. Jon Day joins Tom to discuss lab rats, street rats and the ‘rat in the head’. They explore the reasons many found Calhoun’s rat utopias compelling, and why his conclusions do both rats and humans a grave disservice. From the LRB Subscribe to the LRB: https://lrb.me/pod Close Readings podcast: https://lrb.me/crlrbpod LRB Audiobooks: https://lrb.me/audiobookslrbpod Bags, binders and more at the LRB Store: https://lrb.me/storelrbpod Get in touch: podcasts@lrb.co.uk Learn more about your ad choices. Visit megaphone.fm/adchoices

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