We generally use dustbins for trash or solid waste in our homes, schools and work places, where waste in the form of papers, organic waste, metals, glass, cloth, etc. are dumped to maintain environmental integrity and ensure cleanliness and sanitation.
Environmental ethics demands that we keep the environment clean and green for a healthy living and to do away with germs that cause serious diseases due to contamination. In this context, some conscientious people play environmentally-responsible roles in keeping the environment healthy by observing cleanliness, planting plants, dumping waste properly, avoiding littering, reusing and recycling materials, reducing less waste, etc.
Having said this, there are some birds and animals that are also very environment-friendly in terms of keeping the environment clean by consuming the dead fleshy and boney materials. Such consumers are known as ‘scavengers’, which have also been referred to as ‘bio-bins’ because these species are serving as natural dustbins to gulp down the fleshy remains mostly left from predators or the trash human beings throw as garbage. Some scavengers are vertebrates such as vultures, hyena, crow, kites, while some are invertebrates such as crabs, beetles, flies, etc.
There are both omnivorous and carnivorous animals that feed on carrion or dead animals, so they play their important role in maintaining the environment clean and removing germs from the environment. Their sharp eyesight and a strong sense of smell help them trace the carrion and rotten food source.
Had there been no scavenging animals and birds, how filthy and dirty our environment would have been! But nature is performing this role of environmental sanitation with the help of these bio-bins. It is believed that the role of scavengers and decomposers is so significant in the ecosystems that in their absence, dead bodies would not decompose on the surface of earth.
Scavengers also play an important role in the food web as they break down organic material and recycle it into the ecosystem as nutrients to maintain a healthy habitat. When an animal is rotting, it serves as incubator for many infectious materials which become a health hazard to living animals because of the diseases that can easily spread. Here scavengers play their important role of eating them and quickly breaking down the dead biomass for the benefit of all living organisms. In this way, they serve as natural recycling machines.
They are well-adapted to many places as they would feed on any meat, whether fresh or rotten, as compared to animals with restricted diet. There is also competition among the scavengers when they gather at a carcass — the greater the number of scavengers, the quicker becomes the consumption and removal of the carcass.
All scavengers that perform the clean up duty should be appreciated as they make our world a cleaner place, because they are serving as ecosystem guardians.
Vultures are the most notable and specialised scavenging birds that help clean dead and decaying animals from the environment. Vultures are full-time true scavengers that survive on carrion. They soar up in the sky with a wing span of about six feet and can easily locate a carcass from a great height because they have very sharp eyesight.
They turn a rotting body into bones in a matter of few minutes. Vultures are usually bald, which also protects them from sticking germs on their neck. Moreover, they have highly acidic stomach and the bacteria they eat with the rotten meat are killed in the stomach. If there were no vultures, the rotting meat would be consumed by bacteria and maggots, which are disease-causing agents and carriers. It could be more dangerous to other animals and human beings.
When vultures soar high in the sky, other scavengers get the signal that a feast is nearby and they soon arrive at the site too. Bearded vultures feed on bones rather than the meat.
Hyena is the most noticeable scavenger among mammals. When in a group, they would consume large dead animals very quickly, so much so that they consume their bones with the help of their stout teeth and their powerful stomach easily breaks down bones and digests them.
With the help of their strong sense of smell, hyenas are able to detect carrion from as far as four kilometres. They are so powerful that a pack of hyena would snatch the carrion from other carnivores such as lions. They are also able to hunt on their own. These are common in the African Savannah. Hyenas are very quick to arrive at the site of a kill, sometimes even before vultures.
Bears are powerful omnivorous animals, but are also good scavengers. They are also environment-friendly animals and though they feed on fish, vegetation, fruits, nuts, berries, they would also search for carrion and dead remains of animals.
Bears are also seen around human habitation where food junks attract them to find rotten meat. Bears often follow ravens in order to find dead fish to eat. Alaskan brown bears feed on dead seals, walruses and whales that have floated ashore. In most nature reserves, they raid dustbins for food remains.
Jackals and foxes
Jackals and fox often scavenge. They eat carrion, especially in winter when food availability is a problem. They are nocturnal and are able to hunt also. With the help of their strong teeth, they can tear apart a carcass. Generally, they eat small mammals, birds, and reptiles.
Jackals are very clever animals as they bury their food, to eat later on, if they see another intruder. Jackals are very aggressive scavengers; they even fight with vultures and lions over a carcass to get their meal. Foxes are also scavenger in nature, and they can also be a pest in the cities where they search for rubbish.
Other animals that would scavenge include dogs, wild boar, coyotes and rats. Lions are also opportunistic scavengers, which mean they eat carcass if fresh food is not available.
Crows are not true scavengers, but they scavenge when they happen to find a dead animal. They find such food in the form of road kills, such as dogs, cats or dead bodies of donkeys, goats, chickens, cows, etc., thrown in the fields.
Crows primarily feed on nuts, seeds and insects, but would also scavenge. They are more often seen around human habitation, garbage dumps and trash, looking for meat contents. Research has shown that crows perform a great role in keeping the environment free from rotting and decaying animals.
Other scavenging birds include marabou, storks, eagles, magpies, jays and seagulls.
Insects and sea scavengers
Many insects are scavengers and they help in clearing away rotting flesh and vegetation. Ants eat almost anything. Some ants are scavengers that eat dead plant materials and meat, besides other food items and liquids.
Australian ant and bulldog ants are famous for scavenging and help in recycling organic material whether fruits or insects, which help to keep the environment free of rotting material.
Blowflies are scavengers whose larvae, called maggots, feed on carrion. They also feed on the wounds in livestock by eating dead flesh around the wound. Similarly, cockroaches are good scavengers. They survive very well in places where there are more scavenging opportunities. They have a bad reputation for being pests and spreading diseases because they interfere in the human environment. Mostly, they are seen in kitchens where there are more food sources. Some beetles and crickets also scavenge.
Sea creatures, including crabs, lobsters, eels and white sharks, also go scavenging. In addition, the aquatic crocodile also scavenge on the dead carcasses along the waterways.
Published in Dawn, Young World, November 18th, 2017