Hunting and Feeding: Lion (Panthera leo)

Lions are extremely good hunters, equipped with creamy tan to brown coats that blend perfectly with the sub-Saharan habitat, they are excellent at both ambush and cooperative pack hunting (Stander, 1991). Lions inhabit parkland and open savannah in sub-Saharan Africa – some Asiatic sub-species inhabit northwest India – and can grow from 1.7-2.2m long, are cream tan to brown and have distinct tail tufts, with males typically having a thick mane the may be dark in colour (Scheel & Packer, 1991).

Lions form close social groupings, known as a pride, that are comprised of a number of related adult females and their young (Uhlenbroek, 2008). Males tend to live alone or in small groups called coalitions, however, when they take over a pride the males – one of which will be dominant – are responsible for marking territory borders, which can range from a few tens to a few hundred square kilometres, defending against threats and mating with the females (Mosser & Packer, 2009).

In addition to their capacious size and formidable teeth, lions have supplementary attributes that add to their efficiency as predators; exceptional binocular vision enables them to judge distance very accurately, and eyes that are capable of working at low light levels allow night hunting (Stander, 1991). They use their lethal, retractable claws to grasp and ground prey, before they kill it with a neck-breaking bite or asphyxiation (Uhlenbroek, 2008).

Due to the social nature of lion prides, cooperative hunting is prevalent and is an extremely beneficial way to bring down larger prey items (Stander, 1991). Lionesses are lighter and faster than males and so do majority of the hunting (Uhlenbroek, 2008). Although males may be large and strong enough to attack buffaloes, a lone lion is seldom able to take on much larger species such as elephants and giraffes and as such they engage in cooperative hunting which makes kills easier, with less risk or injury and can provide enough food for the entire pride (Hayward & Kerley, 2006). With adult males gorging themselves every three or four days, tending to eat 43kg of fresh meat in one sitting, it is almost critical that larger prey items be used in order to keep up with this demand (Hayward & Kerley, 2006).

The anatomy of a lion’s skull is adapted for the killing and consumption of sizeable animals like zebras, wildebeests, elands and kudus (Uhlenbroek, 2008). Their long, dagger-like canines and large jaw muscles guarantee a strong grip and successful killing bite (Uhlenbroek, 2008). Combined with the intimidating canines, the pointed, sharp-edges premolars and molars – known as carnassial teeth – work together like the blades of shears to slice through flesh with ease (Scheel & Packer, 1991). The lower jaw only moves up and down, so lions tend to swallow chunks of flesh and do not chew, this also allows them to open their mouths to a gaping 25cm (Uhlenbroek, 2008).

Hunting techniques vary in most prides; commonly one lioness will spook and chase prey at speeds of up to 70kph, towards other members of the pride who are lying in wait (Stander, 1991). Alternatively, the pride will surround a herd and try to pick of a lone, young or sick individual (Uhlenbroek, 2008). These cooperative hunting techniques are beneficial in ensuring that once a kill has been made, other competing pack animals such as hyenas, do not come and try and steal the kill (Stander, 1991). These techniques and the cooperation between individuals requires a great deal of forward thinking and communication in order to be effective and gives an indication of the level of intelligence that lions possess (Scheel & Packer, 1991).

Reference:

Uhlenbroek, C. (2008). Animal Life. United Kingdom: Penguin Group.

Hayward, M. W. & Kerley, G. I. H. (2006). Prey preferences of the lion (Panthera leo). Journal of Zoology, 267(3), 309-322.

Mosser, A. & Packer, C. (2009). Group territoriality and the benefits of sociality in the African lion (Panthera leo). Animal Behaviour, 78(2), 359-370.

Scheel, D. & Packer, C. (1991). Group hunting behaviour in lions: a search for cooperation. Animal Behaviour, 41(4), 697-709.

Stander, P. E. (1991). Cooperative hunting in lions: the role of the individual. Behavioural Ecology and Sociobiology, 29(1), 445-454. 

Hunting and Feeding: Orca (Orcinus orca)

Orcas, more commonly known as killer whales, are the largest dolphin species in the world, growing up to 8m (26ft) long (Uhlenbroek, 2008). They inhabit coastal and offshore waters in oceans worldwide from Polar Regions to the tropics, and are characterized by black bodies with white undersides and flanks and prominent white patches behind the eyes (Uhlenbroek, 2008). The dorsal fin of males is very large and triangular, whereas female dorsal fins are shorter and more curved (Uhlenbroek, 2008).

Orcas are extremely intelligent and very social animals, often travelling in large, maternally based pods and communicating with each other using a range of whistling and clicking calls (Brault & Caswell, 1993). There are many physical, behavioural and genetic difference between orca populations and it is unknown exactly how many sub-species, or even species, there are (Uhlenbroek, 2008). Throughout the five distinct orca types that HAVE been identified, a large range of prey are targeting including a variety of fish shoals, sharks, cephalopods, turtles, seals, sea lions and even whales (Baird, 1997).

The feeding behaviour depends on the type of orca and its selected prey; orcas that following migrating shoals of herring either choose to feed singly or work in a group to corral the fish into a tight ball, often sing their powerful tail flukes as bats to stun or kill them (Simila, 1997). Orcas that hunt marine mammals kill their prey by ramming them, hitting them with their tails or tossing them into the air and in shallow waters orcas often beach themselves to feed on prey along the shoreline (Baird, 1997). Orcas that hunt for whales will generally select a calf or weaker adult and chase it to tire it out and separate it from the group, the orcas will then drown it by not letting it resurface for air (Uhlenbroek, 2008).

Orcas also have a very unique cooperative hunting technique for catching seals who are resting on small icefloes known as wave hunting (Smith et al, 1981). Wave hunting begins with a lone orca – or a few – propping its head out of the water in order to spot a lone seal resting on the ice, a behaviour known as spy-hopping (Smith et al, 1981). Once a seal has been spotted, other orcas may join in an attempt to knock it into the sea; several orcas will swim together towards and under the ice floe to create a large wave to wash over the ice and carry the seal into the jaws of a waiting orca or just force it into the sea (Smith et al, 1981). To ensure the seal becomes dislodged, another orca will deliberately bump the ice from one of the sides (Smith et al, 1981).

This technique is an indication of the killer whales intelligence as it relies on complex planning, coordination and communication in order to be effective (Uhlenbroek, 2008).

References:

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Baird, R. W. (1987). Foraging Behaviour and Ecology of Transient Killer Whales (Orcinus orca).  Department of Biological Sciences, 1(1), 1-34.

Simila, T. (1997). Sonar observations of killer whales (Orcinus orca) feeding on herring schools. Aquatic Mammal, 23(3), 119-126.

Brault, S. & Caswell, H. (1993). Pod-Specific Demography of Killer Whales (Orcinus orca). Ecology, 74(5), 1444-1454.

Smith, T. G., Siniff, D. B., Reichle, R. & Stone, S. (1981). Coordinated behaviour of killer whales, Orcinus orca, hunting a crab eater seal, Lobodon carcinophagus. Canadian Journal of Zoology, 59(6), 1185-1189. 

Hunting and Feeding: Whale Shark (Rhincodon typus)

The whale shark is the world’s largest fish, growing from 12 – 20m (29 – 66ft.) (Uhlenbroek, 2008). It has an extremely large head, prominent ridges running along its grey or brown body, and artistically patterned with white spots all over (Stevens, 2006). Whale sharks migrate through oceans all around the world to exploit areas of rich feeding (Stevens, 2006). One such destination is Ningaloo Reef situated off the coast of Western Australia, where whale sharks often congregate to feast on the plankton boom resulting from the mass spawning of corals (Uhlenbroek, 2008).

It is thought that whale sharks are able to determine the best feeding areas through olfactory cues (Uhlenbroek, 2008). They feed primarily by cruising slowly through food rich water, passing water through their mouths and out through their gills, effectively trapping food for swallowing, however, whale sharks have also been known to use their mouths as buckets and swim upwards through a dense patch of food (Martin, 2007). The width of a whale sharks mouth when it is opened fully to engulf prey is approximately 1.5m (Uhlenbroek, 2008).

Whale sharks are not the only filter feeding shark; basking sharks and mega-mouth sharks are also highly efficient filter feeders, equipped with large mouths and gill arches (Martin, 2007). In order to catch their prey, whale sharks synchronise gulping in water and opening their gills, they also create suction from which most fish cannot escape, by expanding their buccal cavity or gulping air at the surface (Stevens, 2006). Water that is pumped through the gills, passes through a sieve of bony projections known as gill rakers, and only potential food particular greater than 3mm are trapped (Uhlenbroek, 2008).

References:

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Martin, R. A. (2007). A review of behavioural ecology of whale sharks (Rhincodon typus). Fisheries Reseach, 84(1), 10-16.

 

Stevens, J. D. (2006). Whale shark (Rhincodon typus) biology and ecology: A review of the primary literature. Fisheries Research, 84(1), 4-9. 

Hunting and Feeding: Common Praying Mantis (Mantis religiosa)

The common praying mantis (Mantis religiosa) is a highly specialized predator and skilled ambusher, growing up to 7cm and living in all kinds of vegetation in Europe and North America (Uhlenbroek, 2008). As an elongated green or brown insect with large, spiny front legs and a distinctive triangular head, the praying mantis perfectly resembles a tree leaf or stick and relies on this camouflage to ambush its prey (Rossel, 1985). Its triangular head is extremely mobile and is equipped with a pair of large compound eyes that face forward and provide the mantis with true binocular vision (Rossel, 1985). Using these eyes is gauges the distance to its prey by moving its head to measure the apparent movement of the prey relative to its back ground (Rossel, 1985). This technique is known as binocular triangulation and is widespread among vertebrates but much less common among invertebrates (Uhlenbroek, 2008).

The praying mantis’ attack is rapid; using acute vision and location techniques it calculates the exact distance, speed and direction needed to catch the prey then launches an attack by fully extending its front legs and flexing its tibiae in a vice-like grip around its prey before retracting back to normal and consuming (Roeder, 2005). The whole attack lasts less than 100 milliseconds (Uhlenbroek, 2008).

In addition to its vision, there are many modifications to the praying mantis’ body that allow for such an attack to occur. Firstly, the front section of the thorax that carries the front legs is extremely long and combined with the elongated front legs, allows the mantis to reach large distances and snatch prey (Roeder, 2005). Secondly, the front femur is greatly enlarged to house the muscles that operate the tibia, and are also equipped with sharp spines on the inner surface (Roeder, 2005). The front tibia, also spined, then folds back like a jack-knife to mesh with the spines of the femur, creating a formidable trap (Roeder, 2005). The middle and hind legs support the insect and are used for walking and holding on to vegetation (Uhlenbroek, 2008).

The praying mantis is primarily a day hunter and feeds on a wide range of insects, spiders and other arthropods (Uhlenbroek, 2008). When prey is caught and subdued, the mantis uses its strong jaws to cut through tissue and chitin with equal ease, with no need for venom, the mantis eats its victims whole and alive, leaving only fragments (Uhlenbroek, 2008).

References:

Roeder, K. D. (2005). The control of tonus and locomotive activity in the praying mantis (Mantis religiosa L.). Journal of Experimental Zoology, 76(3), 353-374.

Rossel, S. (1985). Binocular Spatial Localization in the Praying Mantis. The Journal of Experimental Biology, 120 (1), 265-281.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Hunting and Feeding: Koala (Phascolarctos cinereus)

The koala is a small, grey, bear-like marsupial with characteristic pale ear tufts that lives in eucalyptus forest and woodlands in Eastern Australia and grows to about 72-78cm in length (White, 1999). Equipped with powerful forelimbs, opposable digits and strong claws, koalas are able to move through the trees to reach their food with ease, which they then nip of with their sharp incisors (Uhlenbroek, 2008). They have also adapted modified cheek teeth; a single premolar and four molars with high crowns on each jaw, enable them to grind the tough leaves into a smooth paste for digestion (White, 1999).

Young koalas, after emerging from the pouch, eat a small amount of its mothers ‘pap’; which is a specialized form of faeces that is soft and runny (Uhlenbroek, 2008). This pap is a rich source of protein for the growing koala and also introduces the bacteria needed to digest eucalyptus leaves, into the young koalas system (Cork et al, 1983).

 While occasionally browsing on other tree species, koalas tend to feed almost exclusively on the fibrous leaves of eucalyptus trees (Cork et al, 1983). Eucalyptus leaves are low in protein, high in toxins and extremely hard to digest (Cork et al, 1983). However, the digestive system of the koala has been specifically adapted to deal with this challenge; the enlarged caecum – which at about 2m long is the biggest of any mammal or marsupial – is the site at which the toxins are deactivated and the paste is digested by bacterial fermentation (Uhlenbroek, 2008). This then allows the koala to survive on a diet consisting exclusively of eucalyptus leaves (Cork et al, 1983).

However, this tolerance to eucalypt leaves comes with a price; due to the challenging nature of digestion, Koalas spend almost 100% of their day sleeping and are often prone to disease (White, 1999). Furthermore, the singular diet of koalas is extremely limiting, as forests and woodlands containing eucalyptus trees are destroyed, the koala’s habitat and sole food source are destroyed along with them, leaving this native Australian icon in need of serious help (White, 1999).

References:

               Cork, S. J., Hume, I. D. & Dawson, T. J. (1983). Digestion and metabolism of a natural foliar diet      (Eucalyptus punctata) by an arboreal marsupial, the koala (Phascolarctos cinereus). Journal of Comparative Physiology, 153(2), 181-190.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

          White, N. A. (1999). Ecology of the koala (Phascolarctos cinereus) in rural south-east Queensland, Australia. Wildlife Research, 26(6), 731-744. 

Hunting and Feeding: Giraffe (Giraffa camelopardalis)

The extremely long neck associated with the giraffe is a very beneficial evolutionary adaptation that allows this large animal to compete with many smaller herbivores that inhabit the African Savannah (Pellew, 2009). Due to their intense height, giraffe’s are able to reach well above their competitors and selectively browse the best parts of the tallest trees, feeding primarily on fruits, flowers and fresh shoots on 40 – 60 different species including commiphora, mimosa and even spiny acacia (Uhlenbroek, 2008).

Giraffes possess the ability to nip leaves from between the long thorns of acacia trees due to the presence of long muzzles, flexible lips and a long, dextrous tongue which enables them to reach deeps into clumps of tree branches (Dagg & Foster, 1976). Because their lips and tongue are covered with thick, horny bumps called papillae, giraffes are seemingly immune to the acacias thorns (Dagg & Foster, 1976).

To ensure they have access to sufficient quality and quantity of food – with adults eating up to 35kg a day – the giraffe roams widely and in lean times can consume dried leaves, twigs and even thorns (Uhlenbroek, 2008). Giraffes are ruminants, meaning they possess four stomachs and first chew and swallow their food, before regurgitating and re-chewing, a process that happens several times before digestion is complete (Pellew, 2009).  Uniquely however, the giraffe is able to ruminate while walking, an adaptation which is perfect for their roaming, nomadic lifestyle (Uhlenbroek, 2008).

Reference:

Dagg, A.I. & Foster, J.B. (1976). The giraffe: It’s biology, behaviour and ecology. Van Nostrand Reinhold Co., NY.

Pellew, R.A. (2009). The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis). Journal of Zoology, 202(1), 57-81.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Hunting and Feeding: Alligator Snapping Turtle (Macroclemys temminckii)

The Alligator snapping turtle is a master of disguise; blending seamlessly with the rocks and debris of its river based home it is the ultimate ambush predator (Bowen et al, 2001). This turtle gets its name from the crude but effective method of hunting mainly due to the way it sits with its mouth open like a crocodile or alligator in the sun, then snaps its jaws shut is a swift movement (Pritchard, P.C.H, 1989). These unusual turtles inhabit the lake and river ecosystems of North America and can grow up to 65cm long (Uhlenbroek, 2008).

Because the snapping turtles entire body – including the inside of its mouth and eyes – are the same drab colour and pattern, the long, wiggly, red tongue is the only distinguishing feature that can be seen by prey and resembles perfectly the movement of a worm (Bowen et al, 2001). As such the turtle simply lies in wait, with its hooked jaws held wide open, and wiggles its tongue around in an attempt to mimic the movement of a worm to attract prey (Uhlenbroek, 2008).

Once prey comes close enough, the turtle quickly snaps its hard jaws shut, crushing the prey instantly before swallowing (Pritchard, P.C.H, 1989). The snapping turtles diet consists mainly of fish, snakes and amphibians but they are also know to prey on other turtles or even readily eat carrion if the opportunity arises (Uhlenbroek, 2008).

References:

Bowen, B.W., Moler, P.E., Roman, J. & Santhuff, S.D. (2001). Population Structure and Cryptic Evolutionary Units in the Alligator Snapping Turtle. Conservation Biology, 13(1), 135-142.

Pritchard, P.C.H. (1989). The alligator snapping turtle: Biology and conservation. Milwaukee Public Museum, WI.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Hunting and Feeding: Box Jellyfish (Chironex fleckeri)

The notorious box jellyfish, Chironex fleckeri, is not only among the world’s most dangerous venomous creatures, it is also a very active and formidable predator (Alderslade et al, 1998). The box jellyfish uses the venom in its tentacles not just as a defence mechanism, but also for the express purpose of incapacitating and eating its prey (Marsh and Slack-Smith, 2010). Equipped with as many as 15 tentacles, lined with thousands of stinging cells and armed with over 5,000 specialized barbed nematocysts per arm, the sting from a box jellyfish has the ability to pierce flesh, crustacean cuticle and even the shells of molluscs (Uhlenbroek, 2008). Each cell contains a filament lined with barbs that, when triggered by contact with prey, release explosively and instantly stun and paralyse the target (Marsh and Slack-Smith, 2010). The rapid ejection of this barb is one of the fastest cellular processes ever recorded in nature and turns the barbed filaments inside out with roughly the same energy as firing a small-calibre bullet (Uhlenbroek, 2008).

Belonging to the class Cubozoa, box jellyfish are not true jellyfish but are closely related (Marsh and Slack-Smith, 2010). They are capable of moving at speeds up to 7.2kph by using a form of jet propulsion and are equipped with 24 eyes arranged in four groups of six on each side of the body (Marsh and Slack-Smith, 2010). While most of these eyes are simple organs capable of responding only to light and dark, one pair in each cluster has the ability to form images and may guide the jellyfish to its prey (Uhlenbroek, 2008).

Whilst the box jellyfish usually preys on small fish and crustaceans, they pose a significant threat to humans with its excruciatingly painful stings causing heart failure and shock often leading to drowning (Uhlenbroek, 2008).

Reference:

Alderslade, P., Bloom, D.A. & Burnett, J.W. (1998). Partial purification of box jellyfish (Chironex fleckeri) nematocyst venom isolated at the beachside. Toxicon, 36(8), 1075-1085.

Marsh, L.M. & Slack-Smith, S. (2010). Field Guide to Sea Stingers and Other Venomous and Poisonous Marine Invertebrates. Western Australia, AUS: Western Australian Museum.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Hunting and Feeding: Red Crossbill (Loxia curvirostra)

The red, or common, crossbill is a species of finch whose diet consists almost exclusively on the seeds of coniferous trees (Hahn, 1998). As such they have adapted a distinctive trait that enables them to deal with their specific diet. The unusual crossed bill of these birds allows them to prise open the tough cones of conifers before they ripen and open naturally (Uhlenbroek, 2008, pg 191). Their adapted bill comprises of an elongated upper bill and a shorter, crossed lower bill, which – while common to all crossbill species – can differ in size and shape between species and populations within a species according to their preferred type of cone, be it spruce, pine or larch (Marquiss, 2002).

In order to feed, the crossbill simply inserts its closed bill into a cone and opens the crossed tips, thereby prising open the scale of the cone and allowing the bird to eat the seed inside (Marquiss, 2002). Because of their highly resinous diet, these birds must frequently visit water sources in order to drink and clean off their bills (Uhlenbroek, 2008, pg 191).

The adaptation of this bill gives an advantage over other finches inhabiting the same area due to the ability of the common crossbill to breed whenever the cone crop ripens, even during the winter months (Hahn, 1998).

References:

Hahn, T.P. (1998). Reproductive seasonality in an opportunistic breeder, The Red Crossbill, Loxia curvirostra. Ecological Society of America, 79(7), 2365-2375.

Marquiss, M. & Rae, R. (2002). Ecological differentiation in relation to bill size amongst sympatric, genetically undifferentiated crossbills Loxia spp. International Journal of Avian Science, 144(3), 494-508.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.

Hunting and Feeding

Feeding is fundamental in providing plants and animals with the energy required to undertake various chemical processes within their bodies that are essential for life (Uhlenbroek, 2008, pg 179). There is a wide variety between animals in regards to the food they eat and how it is obtained; from carnivorous bears to herbivorous deer. To achieve this, a range of adaptations have evolved.

Animals are generally classified according to their diet; carnivores eat other animals and so have developed specialized detection methods and behaviours such as stalking, ambushing and co-operating with one another to bring down larger prey (Uhlenbroek, 2008, pg 179).

Herbivorous diets consist of plants and as such they have also formed specialized behaviours that allow them to feed. The evolution of grinding teeth – such as in elephants – allow them to chew tough plants and unique inner organs such as the appendix in koalas allow a diet of entirely eucalyptus leaves (Bollinger et al, 2009).

Omnivores and scavengers feed on a wide variety of food including plants, animals and decaying matter (Clark, 1982). Consequently, they often lack any highly specialized adaptation but instead require the flexibility to utilise such a wide range of food (Uhlenbroek, 2008, pg 179).

These different types of feeding behaviours and adaptations allow for the development of food webs within ecosystems.

References:

Clark, D.A. (1982). Foraging Behavior of a Vertebrate Omnivore (Rattus Rattus): Meal Structure, Sampling, and Diet Breadth. ESA Ecology, 63(3), 763-772.

Bollinger, R.R., Everett, M.L., Fisher, R.E., Parker, W., Smith, H.F.& Thomas, A.D. (2009). Comparative anatomy and phylogenetic distribution of the mammalian cecal appendix. Journal of Evolutionary Biology, 22(10), 1984-1999.

Uhlenbroek, C. (2008). Animal Life. Penguin Group, UK.