Denali National Park, Alaska, United States

What might look like a goofy grin is actually one of moose’s most intriguing behaviors, the Flehmen Response. When a bull curls back his upper lip, exposing his teeth, he’s using a specialized sense of smell to interpret chemical cues in the air. This behavior allows the moose to draw scents into the Jacobson’s organ, located in the root of the mouth, helping it detect whether a nearby cow is in estrus during the rutting season. It’s a vital part of moose courtship and communication, and a glimpse into how instinct, biology, and behavior intertwine in the natural world. Capturing this rare moment offered a rare glimpse into a side of wildlife observation we seldom see: how scent shapes very purposeful cycles of life in the wild.