Ravens Give Wolves a Reason to Live in Packs | The Wolves and Moose of Isle Royale
People who study animal behavior think they may have found out why wolves hunt in packs — because ravens are such good scavengers. Relationships. Aware that I promised this information months ago as a sequel to my first raven story, it has taken me this long to amass more. Very few mammals have symbiotic relationships with other animals. One of the few exceptions is the raven and the wolf. Ravens are sometimes.
The Raven left the raft, flying for a whole day, and saw no land, so Wisagatcak called Wolf to help. Wolf ran around and around the raft with a ball of moss in his mouth.
Wolves and Ravens – Nature’s Odd Couple
The moss grew, and earth formed on it. It spread on the raft and kept on growing until it made the whole world.
This is how the Earth was created. The wolves dragged her down by the haunches and delivered the deathblow by ripping out her throat. They filled their bellies until the distant sun began to lighten the eastern horizon. The wolves then retreated into the nearby timber.
Gazing across the valley, I occasionally glimpse one of the younger wolves moving amid the trees. Standing atop the carcass, a large raven picks chunks of meat from the rapidly freezing body. Other ravens and black-billed magpies soon join it. These scavengers have sought out this kill from some distance away. Watching the ravens, I wonder if the black birds witnessed the hunt that took place the previous night.
Wolf and Raven
Did a large raven, silhouetted against the moon, maintain a watch on the life-and-death struggle, and hope for death? A shy coyote has joined the mob at the carcass. It acts like a scolded child, as it smells the wolves at the kill. It quickly rips off a mouthful and retreats to a safe distance. The small coyote knows if the nearby wolves catch it at their kill, it will mean a quick, violent death from the crushing jaws of its larger canine cousins.
- The Wolf and Ravens
- The Raven and the Wolf—a Study in Symbiosis
- Ravens Give Wolves a Reason to Live in Packs
By the late afternoon, the light is fading and the wolves are rising. A couple of the younger wolves come down to the carcass for a snack.10 Unbelievable Facts That Will Change Your Perception On Ravens
As they approach, the magpies flush in a cacophony of harsh calls. The bird seems to be almost studying the wolves, trying to learn more about their habits.
The pair of wolves turn and lope up the sage-covered hill to rejoin the pack. Later, it was thought that larger packs were more efficient at killing large prey. This also turned out to be not quite right. Decades of observations on Isle Royale wolves showed, quite surprisingly, that as pack size grows larger, each wolf in the pack gets less food. Although they kill moose a bit more frequently, larger packs have more mouths to feed. We began to wonder, could ravens help us understand why wolves live in packs?
Wolves are almost always followed by ravens - waiting to scavenge from the next kill. Typically, between 5 and 20 ravens attend a kill site. Each raven can eat or cache about two pounds of food per day.
Ultimately, ravens can scavenge as much as a third of what wolves kill. Perhaps wolves live in groups to reduce losses to scavenging ravens. Larger packs, despite the cost of sharing with more pack mates, might do better than smaller packs by minimizing losses to scavenging ravens. Assessing this idea, would require accounting for how all the costs and benefits of foraging change with pack size.
After a great deal of calculating and figuring, it seems that ravens offer wolves a reason to live in packs. Wolves living in larger packs lose less of what they kill to scavengers.
The Wolf and Ravens
The red line is what wolves kill on a per wolf basis. The green line represents what each wolf get to eat net energy gain, actually when losses to ravens are taken into account. When you catch something big, you must be prepared to deal with scavengers. Some species, like cougars, lions, and cheetahs hide the carcasses of their prey or cache them out of reach from scavengers.
Wolves have a different strategy. The faster a carcass is consumed, the less that is given to ravens.