Dinner with Friends
Dinner with Friends
Why it can be easier to forage as a group.
Why do we eat together? When you ask Google, it says because we enjoy connection and the chance to be social. Eating together floods us with feel good hormones. But why do animals eat together? To be able to pull down a fully grown buffalo of course! Or you know… if you’re the buffalo to avoid being torn apart by lions. The animal world doesn’t have quite the same idea of family meal time as we do but eating together can still bring them many benefits. Just maybe not the chance for a good conversation over a risotto.
Foraging is a subject that entranced ecologists. It brings in the economic theories and complex equations that strike fear into all but the most mathematically minded biology students. Basically, to be the most efficient forager you can be, you need to consider cost and benefits. Imagine you are a lion. It’s a long, hot day on the savannah and you need a tasty meal. You have a few options. Firstly, you could go off and find a nice tasty buffalo. They provide a massive meal and you have a lot of mouths to feed. But there’s a problem. You don’t know exactly where they are. So you have to calculate whether the energy you gain from eating the buffalo will be worth it, considering the energy you will have to burn looking for the buffalo. And then there’s the horns. You would have to fight it too, risking getting a nasty injury which could leave your pride one hunter down. And before all that you would have to gather enough lions to come with you because you would have no chance of bringing it down on your own. You would have to leave your cubs unprotected because you couldn’t risk bringing them along - knowing them they’d probably end up getting trampled on. So given all the energy it would take to do all that, its probably not worth it today and you might try your luck tomorrow. Instead you might take a pal and bring down a gazelle. Less to eat, but more a better net gain of energy. Delicious.
These are the kind of calculations that foraging entails for animals every day. The same thinking applies to herbivores too, but they are thinking about whether its worth going all that way for a few leaves or whether you should just make do with what you have. They also have to think about how vulnerable they are leaving themselves to predators. To resolve this, many herbivores travel and forage with a group. It can be hard to pay attention to whether you are about to get eaten when you are busy chewing on some delicious acacia leaves and so many eyes mean that someone will probably spot the lion peeking through the shrubs.
There are costs to hunting or foraging in groups though - mainly competition. If you do bring down that gazelle you’re going to need to share it with those that helped you. Or in animal societies with a strict hierarchy, you might need to share it with the ones you left behind basking in the sun while you did all the hard work. And there’s only so many leaves on a tree, so while you are watching out for predators and slowly chewing, your friends can strip it bare.
Considering how and why animals forage can become difficult because foraging behaviour doesn’t exist in a vacuum. You can watch and study how many animals make the optimal group size for the most efficient foraging. But most real groups will deviate from this size because of other factors. You might need to be in an overly large group because you live in territory that is difficult to defend, or you might need to live with only a few others because you have young that need protecting from other individuals. Maybe you are just unpopular and have to go it alone or with a few close allies. There are many reasons why animals deviate from the optimum and this can make applying economic foraging theories to real life situations difficult.
Group size isn’t the only thing that contributes to foraging efficiency. If we compare two African hunters, the African wild dog and the lion, we can see other differences which clearly affect how successful they are. Wild dogs are successful in about 80-85% of hunts whereas lions are only successful about 20% of the time. We can attribute this difference to a few things: Firstly, wild dogs are highly social and create much stronger bonds than lions do. They have a wide range of vocal communications allowing them to coordinate better when hunting, which allows them to more efficiently bring down prey. They are less hierarchal than lions, allowing better group cohesion - they rally together before hunting to solidify them as a team. By hunting together, it allows them to bring down a greater range of prey and improves their ability to defend carcases. Having prey stolen, usually by lions or hyenas, is common for wild dogs and so they need to share the duty of watching out for intruders and defending their kill. They share their kills much more equally than lions too, motivating members of the pack to contribute as they will gain something from it.
Wild dogs use different strategies for different prey, which contributes to their success. For example, they rush at wildebeest hoping to scatter the group and allow them to pick off an individual, whereas they pursue antelope in the hope that they can outrun them. Wild dogs rarely scavenge, so being able to hunt efficiently is crucial for their survival. But it is more than that, they have been seen defending injured or elderly pack members against lions and gathering the group together to bond before a hunt. Their close cohesion allows them to be efficient and successful by relying on each other and using different strategies for different situations.
For wild animals, every day involves decisions that mean life or death, whether that is deciding if you should go after that distant herd of buffalo or whether you should run, rather than fight, if your kill gets stolen. Getting enough food is a daily battle for animals and the right decision needs to be made again and again to make that happen. Unless you are a pet dog, then you just need to put your paw into someone’s hand or wait by your bowl. I think I’d rather be a spaniel than an African wild dog. It’s less hassle.