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 »

World Lion Day – 10th August

Today is World Lion Day, a day when we should reflect on this beautiful animal’s place in our world and more importantly, our impact on its population. The lion (Panthera leo), second largest of the big cats, is the king of the beasts and admired around the world by children and adults alike for its beauty and power.

Male African Lion (Panthera leo)

Male lions (Panthera leo) have a thick mane of hair around their neck to protect them in fighting. Photo Credits.

Lions had a wide range historically; found all over Africa and much of Europe and Asia. As recently as Roman times, Lions were roaming in the wild in Italy and Greece, but these lions have now disappeared. There is a subspecies of modern lion that still lives outside of Africa; the Asiatic lion (Pentera leo persica) still has a small population of around 400 living in the Gir Forest in Gujarat, India.

Asiatic Lion (Panthera leo persica)

Asiatic lions (Panthera leo persica) are a subspecies of lion found in Gujurat India. Lions were once found in many places in Europe and Asia. Photo Credits.

Today there may be as few as 20,000-30,000 lions left in the wild and their numbers are declining. There are many threats facing the world’s remaining lions from farmers killing them to protect their livestock to poachers hoping to sell lion teeth and bones for ‘traditional medicine’.

To celebrate World Lion Day, there are many things you can do if you want to help out lions.

One of the most important things you can do is talk to people and raise awareness; tell people about the plight of lions around the world and suggest that they can also help out.

You might want to donate time or money to a conservation organisation; check out this page on the World Lion Day site to discover a whole range of groups that are working to conserve lions and see if there is any way you can help them.

You can also make sure that you prevent contributing to abuse of lions by avoiding attractions like animal circuses, or zoos/sanctuaries with poor conditions.

Lion cubs (Panthera leo) playing

Lion cubs (Panthera leo) grow up in family groups and males leave to make their own prides when they reach adulthood. Photo Credits.

Hope is not lost and the future for lions could be bright. Ethical and sustainable tourism can bring money to help conserve lions in suitable reserves and conservation groups are working tirelessly on reducing human and environmental impact on lion populations. It is never too late to make a difference and hopefully we can work together to ensure the lion can keep its thrones as king of the beasts for many generations to come.

Much love,

-Nick

3 Comments »

The Albino Tree: Real or Fairytale?

Often in films, animations and especially during Christmas time, we see these images of beautiful white trees; they can be a pine tree, a spruce or even a fir and they stand tall in a decorated home or a frozen forest. Whenever we think or a nice cold Winter we imagine big trees covered with snow, tiny chubby birds trying to survive and nice warm fireplaces. But how often have we actually seen a real white tree? Not a green tree covered with snow or white decorations or even a grey tree on its’ last days, but a true perfectly white tree? Maybe not that often considered that there are only 50 or 60 individuals on our planet Earth.

 

So, does that mean that there is such a thing as an albino tree?
Ah, not so fast!
Before we start answering this very interesting question we must first define albinism.

 

What is albinism?
Albinism is a disorder characterised by the absence of melanin in the organism.
Melanin is the pigmentation that exists in animals that allows us to have a certain hair colour, skin colour and even eye colour. Without it our body is unable to create the colour our genes are ordering our body to produce.
Imagine giving an artist an animal to paint but forgetting to give him the colours to do so. The animal will still exists but without the “correct” look.

 

Now that we know what albinism is..

The white needles of an albino redwood tree (Sequoia sempervirens)

The white needles of an albino redwood tree (Sequoia sempervirens)

Are there albino trees?
Well, technically not because plants don’t have melanin so they would not have a disorder based on the lack of such pigmentation.
The colour we seen in trees (mostly green) is due to the presence of chlorophyll, a biomolecule responsible for photosynthesis, which enables plants (and a few other organisms) to receive energy from sunlight.
The “albino” tree we see in the picture on the right has an absence of chlorophyll and not melanin (as in the case of albinism), although the end result is quite similar.

But if not having a production of melanin in one’s body is hard for animals since it makes them hard to camouflage with the environment and/or deal with environmental conditions such as extreme heat, then not being able to produce chlorophyll in plants is much much worse.

 

If plants can’t produce energy from light how will they even grow up and survive?

The “albino” Coast Redwood or California Redwood (Sequoia sempervirens) manages to survive by, almost like a vampire, sucking the life of a nearby tree by connecting their roots with the closest healthy tree, usually the parent. By doing so, they are able to gain the nutrients they need to develop without using the photosynthesis process. Because of this, the white tree is only able to survive as long as the parent lets it. If times get hard and the parent requires all the nutrients it can get, it will “disallow” the parasitic tree to keep reaching for its resources, therefore condemning it to its death.

 

Now that we know that they do exist (even though technically not “albino”)..

Where can we find these often white trees, often called “phantoms of the forest”?
Unfortunately because they are so rare and vulnerable, most of their location is kept secret. But not all!
There are six “albino” redwood trees located in the Humboldt Redwoods State Park in the Redwood Empire on the Northern California coast in the United States of America.
People that have seen these rare “albino” redwoods claim that their white needles feel like wax, their growth rings are very close to one another which suggest a slow growth and their wood is quite weak but, overall, they are definitely gorgeous looking trees!

 

In conclusion, albino trees do exist and although they are technically not albino, they sure look like they come from a fairytale.

I hope you enjoyed learning about this curious topic and if you ever go visit these fantastic specimens in the Humboldt Redwoods State Park make sure you take a picture and send it to us!

 

Até à próxima.

~Sofia.

Leave a comment »

Follow

Get every new post delivered to your Inbox.

Join 213 other followers