It’s the most pleasant time of the year. Spring is in the air, baseball is back, and the dread days of a burning hot summer remain safely in the future (for now). Step outside, walk around the neighborhood, and you could convince yourself that all is right with the world—unless, of course, you’re a mail carrier.

That’s the takeaway from the annual report from the United States Post Office, which tracks dog attacks faced by its carriers each year. Four of the thirty worst-offending cities—Houston, San Antonio, Dallas, and Fort Worth—are right here in Texas, and Houston outstrips the competition in earning the dubious distinction of being the city with the largest number of dog attacks on mail carriers in the entire country.

Houston is no stranger to the list—last year, it placed second, behind Los Angeles—but this year, the second and fourth most populous cities in the country swapped spots. Houstonian dogs went after the men and women tasked with delivering their missives 71 times in 2017, up from 62 times the prior year. (In L.A., meanwhile, the 80 attacks of 2016 was reduced to 67 in 2017.) San Antonio, meanwhile, tied with Baltimore for #6 on the list, with 44 attacks, and Dallas placed at #8 with 40. Outside of the top ten, Fort Worth tied with San Jose, California, after its dogs attacked mail carriers on 26 different occasions.

There are a few temptingly easy answers: Does Texas get over-represented on the list because of the large population of its cities? Are Houston pet owners less responsible than pet owners in other cities? But either such assessment would be short-sighted. Per capita, Houston’s bad dogs have nothing on the pets of St. Louis, whose population is a fraction that of the Space City. If St. Louis had the same population as Houston, one could extrapolate from the 52 dog attacks in that city that there would be more than 375 attacks on the list, dwarfing Houston’s numbers. That math works the other way, too: despite an extra 1.6 million people, L.A. saw four fewer dog attacks than Houston did, which suggests that if we’re only looking at this as a numbers game, Houston’s dog attacks indicate significantly worse-kept pets in that city than in L.A.

Houston’s propensity towards canine attacks on postal workers is likely due partly to a different factor: lawns. Houston is a city built around single family homes with yards. New York, which doesn’t even crack the top 30 despite a population more than three times that of Texas’s most populous city, is not. Dog attacks are going to be less common in a city where a mail carrier’s rounds mostly involve dropping letters into slots in a mailbox on the ground floor of an apartment building, rather than venturing onto the property of a resident who may not keep their pet under strict control. (That probably helps explain why the much larger city of Los Angeles, which has its share of both kinds of properties, comes in second on the list.)

Meanwhile, the rest of the state tracks fairly consistently with population: San Antonio, the seventh largest city in the nation, comes in at #6 on the list, two spots ahead of the ninth-largest, Dallas. Fort Worth, smaller than either, slides all the way to #15. (Austin, with 100,000 more people than Fort Worth, doesn’t place at all, presumably because all of the dogs are vegan.)

Regardless of the reasons for canine malice, there are a few things that pet owners can do to help avoid the number of dog attacks that mail carriers face, starting with posting a sign letting postal workers know that there’s an animal in the yard so they can take appropriate caution. For more on this, check out the USPS video suggesting other ways for dogs and mail carriers to safely co-exist.