The cool, crisp air of autumn encourages longer outdoor activities for dogs and their owners. However, allowing your dog to leap into piles of leaves may not be the best idea.

Veterinarians caution that fall can introduce unexpected dangers to dogs while they play outside. Each year, they treat dogs who get hurt after leaping into leaf heaps hiding hazardous objects like sharp sticks, metal fencing, and other debris, according to Joanna Woodnutt, a veterinary surgeon from the UK. As the climate cools, more pet owners tend to let their dogs off-leash because the drop in temperature allows the dogs to play longer without tiring.

“People take their dogs to parks and let them run free,” she noted, adding that it is surprisingly common for owners to encourage their pets to jump through leaves.

Woodnutt also warned that acorns and fallen fruits can be harmful if dogs chew on them. During the cooler season, it is crucial to keep older dogs, especially those suffering from arthritis, warm and comfortable.

“While autumn is a beautiful time to enjoy outdoor activities with our pets, there are important safety considerations to remember,” Woodnutt advised.

Check Leaf Piles for Hazards

Woodnutt has witnessed injuries in which dogs got impaled by sharp items after jumping into leaf piles. A large, pointed stick could potentially pierce a dog’s chest or abdomen and could be fatal, she cautioned.

Veterinarian Dana Varble also reported an increase in paw injuries and scratches among dogs this season. The autumn months often bring more burrs and sticks, which can tangle in a dog’s fur and sometimes lead to emergency grooming, she explained.

If dogs are off-leash, especially in the evenings when it gets dark earlier, they may easily run into trouble, Woodnutt noted.

Angela Laws, who runs the popular pet-sitting service Trusted House Sitters, suggests steering clear of unknown hazards when walking dogs outdoors.

“Many videos on social media show dogs leaping into leaf piles, leading everyone to believe it’s fun for them,” Laws pointed out. “Instead, it’s better to create your own leaf pile for safe play,” she suggested, urging dog owners to make a pile themselves.

Before letting your dog dive into a pile of leaves, it’s wise to inspect it first, according to Woodnutt.

“Walk through the pile yourself to check for sharp objects, and don’t just rely on your boots—feel it with your hands,” she advised.

Dangerous Foods: Walnuts and Tree Fruits

Woodnutt noted that some acorns and chestnuts that fall can block a dog’s digestive system or release toxic substances if their shells crack when chewed.

Additionally, walnuts can be problematic, especially the large varieties found on trees, as they may grow toxic mold dangerous to dogs, according to veterinarians. Their sizable, round shape and fuzzy green husk are telltale signs, experts warn.

These walnuts differ from the ones sold in stores, as Varble, chief veterinary officer for the North American Veterinary Community, explained that the mold they harbor can lead to neurological issues if ingested by pets.

Fruits from trees can also pose risks. Overripe or decaying fruit can ferment and contain alcohol, potentially leading to intoxication in dogs, Woodnutt cautioned. She has encountered dogs requiring treatment for mold poisoning after eating spoiled fruit.

Children should also be advised not to toss large acorns when playing with dogs, as dogs might mistake them for toys, Laws emphasized.

Woodnutt shared that she had to perform surgery on a dog that had been “snuffling” through a heap of crab apples on the ground, eating them, while also unintentionally swallowing a small green toy ball that looked like an apple.

Unfortunately, Varble noted, “some dogs can be quite indiscriminate eaters.”

Older Dogs, Like Humans, Feel Cold

During her pet-sitting experience in Manhattan over the Christmas holiday, Laws mentioned that she enjoys taking dogs for long walks in Central Park.

“Alfie was my favorite tour guide; his walk around Central Park was beautiful, especially with the snow, and he loved playing in it,” said Laws, who hails from Cove, a small village in northwest Scotland.

Whether your dog is having fun in the snow or just running around in chilly weather, ensure you help them dry off and warm up inside, as advised by Woodnutt.

“Aging dogs often experience more discomfort in their bones and joints during the fall and winter due to the cold,” she explained. “Many older dogs suffer from arthritis.”

Whether you’re in the country or the city, “walking with a dog is far more enjoyable than going solo,” stated Laws.

To keep your dogs content and healthy during their autumn outings, it’s important to recognize that some seemingly charming activities in colder conditions “aren’t always as pleasant and cozy as they appear.”