Wildlife TV

Learn interesting and funny plant and animal facts with videos and photos

Hematophagia: Vampires are Real!

Animals eat all sorts of things. The diversity of species in the animal kingdom is matched by the diversity of diets. In previous posts we’ve seen how some animals will eat bones (osteophagia), rocks or soil (geophagia), and even faeces (coprophagia). The next ‘phagia‘ we’re going to look at is hematophagia; feeding on blood.

When we think of feeding on blood, the animals that come to mind are blood sucking leeches and pesky mosquitoes but in reality, it is a widespread feeding behaviour utilised by a broad range of species. There are two categories of animal that feed on blood, obligatory and optional; some animals exclusively feed on blood (they are obliged) and some just supplement blood into their regular diet (it is an option). We call animals that feed on blood ‘sanguivores

So why does blood make a good meal? Blood carries vital chemicals around the bodies of many animals and as is loaded with nutrients, proteins, salts and fats; it is a nutritious and high energy food source. Most predators, such as big cats, will gain the nutrients found in blood because they eat all of an animal’s tissues, but hematophagy is used to describe when animals specialise in feeding on this valuable food resource.

Common Vampire Bat (Desmodus Rotundus)

There is nothing supernatural about vampire bats, they are simply an animal adapted to a specific diet. Photo Credits.

Blood is, of course, kept inside animals’ bodies, so in order to drink it, a certain amount of ‘surgery‘ is required. The process of accessing blood is called phlebotomy, it involves cutting into flesh and revealing veins, arteries or capillaries. The tools used by hematophagic animals are almost always their mouth-parts but there are many different anatomical approaches.

The first part of phlebotomy is cutting the flesh; mosquitoes (family: Culicidae), ticks (superfamily: Ixodoidea) and other blood sucking invertebrates have sharp mouth-parts that pierce the skin and dig down to find a source of blood, they then suck up the liquid or let the victim’s blood pressure force the blood into the diner’s mouth. Vampire bats (subfamily: Desmodontinae), found in Central and South America, have a slightly more crude and messier method, they simply use their teeth to slice open their victim’s skin and then lap up the pool of blood that comes out of the wound with their tongue. Interestingly, vampire bats will also use their teeth to trim fur away from the site where they intend to feed.

Anopheles stephensi

This mosquito (Anopheles stephensi) is feeding on human blood by piercing her mouth-parts through the host’s skin. She is digesting the rich nutrients and expelling the excess liquid. Photo Credits.

So vampires are real, but they aren’t supernatural beings, they are animals looking for a good meal, and there are many different species.

Vampire bats are a special group of bats that have become specialist blood drinkers, hence their name. They do not rely on echolocation like many other bats but instead they have specialised senses for finding sleeping mammals on which they can feed. They sniff out carbon dioxide (CO2) and chemicals found in sweat, and have special thermoreceptors on their noses which allow them to detect heat; this also allows them to find warm spots on an animal’s body where blood is closest to the surface.

Vampire Bats (Desmondus rotundus)

These common vampire bats (Desmodus rotundus) are being given a free meal of fresh blood, but in the wild they specialise in stealing blood from sleeping mammals. Photo Credits.

Mosquitoes are perhaps the most famous blood suckers, however, in reality they are not exclusively hematophagic. Not all species of mosquito feed on blood, and for those that do, it is only the females. This family of flies has evolved to feed on nectar and fruit juices but the females of some species have adapted their mouth parts and specialise in drinking blood from the bodies of mammals or birds. But why only the females? The reason for that is related to the nutritiousness of blood as a food source; they use the extra nutrients to help in egg production and development.

Sanguivorous animals are generally parasites; they take blood from their hosts and give nothing back in return (except maybe for a nasty disease). There is one animal that until very recently was thought to be beneficial to it’s hosts, but the relationship is not what it seems. Oxpeckers (genus: Buphagus) are Southern African birds that spend their time riding large grazing animals around, feeding (mostly) on ectoparasites such as ticks. A large animal like a giraffe (Giraffa camelopardalis) has a lot of surface area and a lot of blood and as such attracts a lot of parasites. Oxpeckers have found that riding along on a giraffe is a great way to find all the food they need. It used to be assumed that oxpeckers provided a wonderful service to the large mammals of Africa but recent studies have shown this might not be the case. Although oxpeckers are very fond of ticks (which are already full of blood), they also practice hematophagia and will regularly drink fresh blood from wounds on their host mammal’s body. Oxpeckers will even open up wounds and prevent them from healing so that they have a regular source of blood, this can be painful for the animal as well as putting them at risk of infections.

Yellow-billed Oxpecker (Buphagus africanus)

The yellow-billed oxpecker (Buphagus africanus) is one of the two species of African bird that feed on mammals’ parasites. Recent studies have shown they might cause more harm than good by keeping wounds open to drink blood. Photo Credits.

Hematophagy in practice can be a risky business; anyone who has been bitten by mosquito knows that their first response is usually of aggression and the same is true for other animals. Feeding on an animal’s blood requires physical contact and if caught, there is a possibility of being attacked or even killed. However, blood is such a valuable food resource that many animals are willing to take on these risks in order to obtain it, and many of them have a few tricks that help them get away with it.

Most blood drinking animals have special saliva that delivers a cocktail of chemicals into the bite site when they start to take blood. Their saliva can contain anaesthetics that prevent the host from feeling the bite and reacting to it, and also anticoagulants which prevent the blood from clotting so that it stays liquid and drinkable.

Animals have formed complex relationships with one another when it comes to feeding. When we think of animals feeding on other animals we tend to imagine large predators killing and devouring their prey, but in reality, some species have developed techniques for getting the sustenance they need without so much theatrics.

Much love,

-Nick

2 Comments »

Mating for Life Part 3: Monogamy in Insects

We’ve seen in part 1 (birds) and part 2 (mammals) of this series that there is a lot of variation in monogamy in the animal kingdom. It is worth mentioning one more group of animals before we carry on.

  • Do insects mate for life?

In the invertebrate world, there is a countless variety of mating techniques, but even amidst this variety there are some examples of monogamy and mating for life. Termites (infraorder: Isoptera) are colonial animals where a single queen produces all the offspring that then grow up to service the collective. A termite queen constantly produces offspring, most of which become workers and soldiers that serve the colony, but each year, the queen will produce a generation of breeding individuals. These ‘breeders’, called alates, are males and females with wings that fly away from the home colony to found their own. Females breed and then head underground where they will stay for the rest of their lives producing young. In many species of termite, a queen will keep a single male at her side, a king, who will mate with her throughout her life and he will be her sole partner and father to the entire colony.

Termites surrounding a queen

A termite queen is a huge, egg producing machine (she is the blob in the middle of this picture); all termites in her colony are her offspring but sometimes she is accompanied by a king for her entire life. Photo Credits.

Many species of insect, such as mosquitoes (family: Culicidae) are monogamous because they do not live long enough to be anything else! They hatch from their eggs as larva and spend most of their lives in a larval form. Eventually, the larvae transform into their adult form and emerge, they will then seek to find a single mate with whom they will reproduce and then die. The adult stage of many insects’ lives are dedicated to the sole purpose of producing a single batch of eggs. You could argue whether this counts as monogamous or is just the force of circumstance.

Mosquito

Mosquitos are monogamous mostly because they die not long after they mate for the first time! Photo Credits.

The invertebrates make up the majority of animals on Earth and there is of course a lot of variation within their behaviours, however, monogamy and mating for life is very much uncommon.

In the next post, we will look more at the advantages of monogamy and faithfulness to a mating partner and some explanations as to why some animals have adopted this mating technique.

Much love,

-Nick

3 Comments »

[Top 10] ~ October 2013 Photos

This past month has been crazy. Many things happened (most of them bad unfortunately) but I still managed to get some nice photos. This time I was mostly focusing on getting photos from my surroundings, images of species that are seen so many times around the reserve that most people don’t look twice. I still hope you like it!


A beautiful specimen of a Cape White-Eye (Zosterops pallidus) on a nearby tree.

A beautiful specimen of a Cape White-Eye (Zosterops pallidus) on a nearby tree.

A male Chacma Baboon (Papio ursinus) keeps track of his surroundings to help protect his troop.

A male Chacma Baboon (Papio ursinus) keeps track of his surroundings to help protect his troop.

A Helmet Guinea Fowl (Numida meleagris) making a lot of noise.

A Helmet Guinea Fowl (Numida meleagris) making a lot of noise.

A robber fly, a very strange looking insect.

A robber fly, a very strange looking insect.

A beautifully coloured solifuge, one of the most interesting types of arachnids.

A beautifully coloured solifuge, one of the most interesting types of arachnids.

A Southern Rock Agama (<em>Agama atra</em>) gets a well deserved sunbathing on a large rock.

A Southern Rock Agama (Agama atra) gets a well deserved sunbathing on a large rock.

A Warthog (Phacochoerus africanus) sniffs the area looking for food.

A Warthog (Phacochoerus africanus) sniffs the area looking for food.

A male Chinspot Batis (Batis molitor) rests on a tree branch.

A male Chinspot Batis (Batis molitor) rests on a tree branch.

An African Striped Skink (Trachylepsis striata) enjoys the afternoon sun of the African savannah.

An African Striped Skink (Trachylepsis striata) enjoys the afternoon sun of the African savannah.

A dung beetle frantically rolls a fresh ball of a very special dung.

A dung beetle frantically rolls a fresh ball of a very special dung.

Até à próxima!

~Sofia.


If you liked this entry, make sure you check out our Photography category.
Previous Photography entries:
[Top 10] ~ September 2013 Photos
[Top 10] ~ August 2013 Photos
[Photo] Cheetah with kill
2 Comments »