Over its 400-year-long history, New York City has collected an assortment of emblems that draw the mind toward the famous metropolis. The \u201cI lots of rats<\/a>. <\/p>\n The most modern estimate places NYC\u2019s rodent population at about three million\u2014roughly one-third of the city\u2019s human population. To understand these whiskered residents a little bit better, scientists from New York City<\/a> (and also Germany) studied the behavior of the animals using an assortment of digital technologies, including artificial intelligence techniques (for capturing movement patterns), thermal imaging, and ultrasonic audio recordings. <\/p>\n Related Story<\/p>\n The goal was to understand the behavior of the New York City rat (Rattus norvegicus) in comparison to the characteristics of rats as reported in broad scientific literature. In a study published on the preprint server bioRxiv<\/a>, the team reports that the rats modulate their communication (via ultrasonic squeaking) to match the surrounding sonic environment. After meticulously analyzing three NYC ecosystems<\/a>\u2014sidewalks, city parks, and the subway\u2014the data showed that rats in the subway system communicated more loudly due to the raucous environment. <\/p>\n \u201cThere is an increasing interest in studying animal cognition in natural habitats, especially in light of new AI tools for quantifying behavior,\u201d the authors wrote in the study. \u201cThe advent of new tools may make it possible to translate mechanistic biological insights from laboratory based studies to natural habitats<\/a> where animals live.\u201d<\/p>\n By utilizing a deep neural network to analyze rat vocalizations, accounting for the difference in ambient noise<\/a> (the subway was around 12 decibels louder than the park, for example), the team found that the NYC rat vocalizations were \u201cconsistently shorter duration and lie outside of the historical frequency-duration range\u201d that is typically reported in meta-analyses of brown rats. Speaking with Scientific American<\/a>, Emily Mackevicius, a co-author of the study from the Basic Research Institute, said that rat vocalizations were particularly attuned to their surrounding environment. <\/p>\n Related Story<\/p>\n \u201cThere was an ambulance<\/a> going by, and you could look at that in the spectrogram, and the rat vocalizations were louder than the ambulance,\u201d Mackevicius told Scientific American. \u201cThey\u2019re just kind of screaming to each other, but we just don\u2019t hear it.\u201d<\/p>\n Video of the rats also showed social dynamic trends. Smaller rats (probably juveniles) traveled in groups, likely still learning the foraging<\/a> ropes. Meanwhile, bigger rats tended to be loners. <\/p>\n