A friend recently sent me this interesting email, illustrating what I've always suspected: there appears to be a strong relationship between shelter intakes and the weather.

Subject: Lost Cats and Heat

A week ago I received an unusual call from Eric Swansen, Managing Director of the Regional Animal Services of King County. He had looked at the statistics of lost cats and thought there was a temperature relationship...more cats being brought to the shelter during and after periods of warm weather. Eric has a spreadsheet with the cat intakes and he asked whether I would get the temperatures and we would see the relationship with lost cats.

I asked UW staff member Neal Johnson to get me the Seattle-Tacoma Airport data and I made a few plots. Lets take a look! (see below). The light blue line is the daily average temperature and the dark blue lines are cat intakes into the county animal shelter in Kent. The period ranges from the beginning of 2007 to a few weeks ago.

Eric Swansen was right! A lot more cats show up at the shelter when the temperatures are warm during mid-summer than during the winter. We are talking about roughly a 4 to 1 ratio. Cooler summers, like the last two, have had less stray cats. But there does seem to be a long-term trend independent of temperature, with less cats coming to the shelter.

Talking to Eric we speculated why this relationship with temperature occurs. One possibility is that people leave their doors open more during the summer or let their cats out more when weather is warm, and a certain percentage get lost. He also suggested that cats tend to go into heat when temperatures warm (spring and summer), and thus we would expect the maximum input of kittens to come several months after warming weather.

To get a better idea of the phasing of temperature and cat intake at the shelter, here is a blow-up of the first year. Not much of a phase difference... temperature peaks in July and August, while cat intake is pretty high and flat from June to early October. This is out of my area of expertise!

Just to completely nerd out on you, here is a scatter diagram showing the relationship between cat intakes and temperature, with a trend line added.

Clearly, there is a relationship between temperature and cat intake, but there is a lot of scatter and variability in the relationship as well. Just like the temperature impacts of greenhouse gases on global temperatures! (sorry, couldn't help myself). The other possibility, of course, is that temperature is just a proxy for season and that the role of temperature itself is less central.

Eric and I talked about the lost dog/cat problem and we agreed that so much could be done using social media and the internet to RADICALLY improve the situation. Right now there are many separate lists of lost or found animals (e.g., King County's, Craig's List, etc.) and some animal shelters have no electronic lists or online web information (e.g., PAWS). To start, we need all shelters to list their animals, with pictures, and to bring it all together in one master list that is easily searched.

But this is just a start. We need smartphone apps where you can snap a picture of stray animals and quickly send it to a central site, where the geo-located pictures could be logged and put online. Could you image the power of this? Many folks don't want to approach stray animals, but would be happy to snap a picture of one! My gut feeling is that we could radically reduce the number of lost pets with a modest investment in technology. And I suspect there would be many volunteers that could help make such an advanced system a reality. Such a system could be self-supporting as well, since many folks would be happy to pay a reasonable fee for help in getting their loved pet.

We pride ourselves in living in one of the high-tech capitals of the world--we should have the most advanced stray animal recovery system in the world!