 We've all seen stray cats wandering our neighborhood, sometimes killing native wildlife, sometimes starving and sometimes pulling our heart strings. So what is the best way to deal with the kitty crisis? Well, researchers at the University of Guelph are using science and math to answer that question. This is your Cipod. In a paper published in the journal PLOS ONE on February 28, 2018, Dr. Tyler Flockhart and Jason Koh presented a mathematical model that predicts the populations of cats in urban areas. They use a unique approach where the total cat population is split into four parts, owned cats, stray cats, feral cats and cats in the shelter system. They account for cats moving between categories, such as when owned cats are lost or abandoned and when cats are adopted from the street or from shelters. The model uses data on survival rates and sterilization rates of the different cat categories and calculates for cundity or the breeding rate for female cats in each population. It uses data on adoption rates and abandonment rates to judge how cats transition between populations and it even takes into account the changing length of cat breeding seasons across different latitudes. The model only requires three inputs to be tailored to each individual city, geographical location, number of human dwellings and the urban area. This model was designed to be as simple to use as possible so that policy makers can use it as a tool when planning cat management strategies. It is hoped that this model can predict the effects of different strategies, such as feral euthanasia programs or trap new to release programs and whether these will actually have the impact that the community wants. But does this actually work? Well, this model was validated by comparing it to studies where cat populations were measured in the field. It performed exceptionally well, matching the numbers for owned and sheltered cats. It seemed to overpredict the number of outdoor cats, however, if you've ever tried to trap a feral cat, you might know that it's not the easiest thing in the world to do. Most official estimates of feral cat numbers are based on the number of feral cats trapped, which could be leading to low estimations of outdoor cat populations. So maybe this model might actually be closer to the truer number. Interestingly, the model also found that the number of cats in shelters would drop when there was an increase in sterilization rates of all cat categories, owned, stray and feral. And finally, it also found that total cat population size was most affected by the breeding rates of unowned cats. So sterilizing unowned cats would lead to the greatest decrease in total cat population size. Thanks for watching. If you liked this video, don't forget to like and subscribe to our channel, and you can always catch us live every first Saturday of the month at twenty-hundred UTC. And until next time, keep on discovering.