Hello and welcome to my latest edition of this paleontology blog. This time I have chosen to write about some of the amazing predatory adaptions dinosaurs employed to take down their prey and the equally amazing measures prey species took to try and protect themselves against this. As always I hope you enjoy reading the publication.
Spinosaurus.
Potentially
reaching up to 18 metres in length and with an enormous sail on its back,
spinosaurus would have been a formidable sight. In fact this may have been the
largest carnivorous dinosaur to have walked the planet. There were two species of
spinosaurus, Spinosaurus aegyptiacus and Spinosaurus
maroccanus. The name spinosaurus translates as spine
lizard, which is appropriate as their massive spines could have measured up
to seven feet in length. It is widely suspected that they were connected to
each other by skin to form the sail. No one can be certain what the purpose of
the sail was however theories have included courtship displays and for
thermoregulation.
In 2010, research on isotopes
found in spinosaurus teeth showed that this dinosaur spent a substantial amount
of time in water, further supporting the mounting evidence to suggest this. Spinosaurus
remains have also revealed a variety of adaptations which would have aided its
predatory lifestyle. With nostrils high on its snout spinosaurus would have
been able to largely submerge itself in water, while pressure sensors it the
skull would have alerted it to nearby prey. Conical teeth were perfectly adapted
for catching the aquatic prey spinosaurus would have hunted, which included ;
coelacanths, lungfish, sawfish and sharks although evidence has also been found
to suggest this dinosaur was not above scavenging non aquatic prey. Other
adaptions for a lifestyle in and around water included an open medullary cavity
for buoyancy control and flat bottomed pedal claws associated with foot movements
in water. This awesome predator would have terrorised any prey unfortunate
enough to cross its watery path and without a doubt deserves its fearsome
reputation.
http://media1.s-nbcnews.com/i/newscms/2014_37/661471/140911-spino5_b5ac60e2f46805dfd895cfee61e4341c.jpg
Science Uncovered - Dinosaurs Rediscovered.
A free meal is an easy meal.
Jurassic Park may have portrayed
Tyrannosaurus Rex as a fearsome predator, the truth for a long time however has been a lot less clear cut. The anatomy of tyrannosaurs have caused debate as to
whether they were predominantly scavengers or predators. The tyrannosaurs brain
possessed a large olfactory bulb essential for processing smells, while strong
teeth for breaking and puncturing bones and small forelimbs would also point
potentially towards a scavenging way of life. A publication in 2013 however
proves definitive evidence that of the tyrannosaur species, t-rex at least did
actively hunt prey. A tyrannosaurus tooth was found embedded in the tail
vertebrae of a duck billed hadrosaur in the infamous Hells Creek Formation. This
sort of find is not necessarily unusual. What made this find special was the
clear evidence of bone growth around the tooth. This would seem to prove the
hadrosaur not only escaped but also lived for a considerable period of time
afterwards. It is deemed likely that predatory dinosaurs were similar to modern
day predators in that they may have taken live prey as a preference however
would not have turned down the opportunity of an easy meal through scavenging.
Velociraptors made infamous by Jurassic Park, are an example
of a notoriously lethal predator who also took advantage of a free meal on
occasion. When bite marks courtesy of a velociraptor were found on the remains
of a protoceratops along with the loss of two of its own teeth, it provided the
evidence needed for experts to confidently say this was an occurrence of
scavenging behavior. David Hone of Institute of Vertebrate Paleontology and Paleoanthropology
of China in Beijing points out that with so much meat on offer to the predator
responsible for the kill, it would have made no sense to start feeding on some
of the less preferable parts of the body. He is confident the velociraptor would
have discovered this kill with very few scraps of meat remaining hence the
effort taken to access them. These remains are in sharp contrast to the famous
and amazing find of velociraptor and protoceratops frozen it time in the middle
of a battle to the death.
http://dx.doi.org/10.1073/pnas.1216534110
http://www.livescience.com/11006-velociraptor-frozen-time-scavenging-larger-dinosaur.html
http://paleobiology.si.edu/dinosaurs/info/everything/behavior.html
http://www.livescience.com/11006-velociraptor-frozen-time-scavenging-larger-dinosaur.html
http://paleobiology.si.edu/dinosaurs/info/everything/behavior.html
A lethal claw.
The second claw on
hawks and eagles may closely resemble the shape and function of the sickle
dromaeosaurids employed to help them dispatch prey. While small prey can
largely be dispatched through crushing, larger prey requires a forceful grip to
prevent an escape and the victim is usually subsequently eaten alive. This may be a grim modern day example of how dromaeosaurids would have
predated on larger prey as experts state they lacked any obvious adaptions to otherwise kill their prey.
An example of how initially similar anatomically dinosaur
groups adapted of fill different niches would be the troodontids and the
dromaesaurids. Troodontids opted for speed as a result of a longer metatarsus
along with an accurate albeit weak grip meant potentially a preference for small
prey. Dromaeosaurids with their stronger and slower feet would likely have relied
on ambush tactics and targeted larger prey.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028964#pone-0028964-g011
Venom.
It was thought that a pocket found at the base of the sinornithosaurus fang may have provided evidence that this predator may have used venom to subdue its prey. This has since been disputed however so consequently there remains no conclusive proof of the use of venom by dinosaurs.
Explore Magazine - Dinosaurs Undiscovered.
It was thought that a pocket found at the base of the sinornithosaurus fang may have provided evidence that this predator may have used venom to subdue its prey. This has since been disputed however so consequently there remains no conclusive proof of the use of venom by dinosaurs.
Explore Magazine - Dinosaurs Undiscovered.
Majungasaurus - The cannibal.
Roughly seventy million years ago the island of Madagascar provided a home for one of the most fearsome predators to have ever walked the planet. Majangasaurus was an albelisaur and possessed the characteristic larger blunt skulls and horn associated with these dinosaurs. The narrower skulls found in most theropod dinosaurs would have restricted movement in the neck and meant that prey would have been taken down by repeated much bites much like wolves do today. Majangasaurus on the other hand with its bulkier skull, would have been able to dispatch its prey with a single bite to the skull or neck in the same way big cats do.
Majangasaurus was the top predator of Madagascar and the fossil record provides compelling evidence that this dinosaur was not adverse to predating on its own kind when prey supplies were short. Their remains have been found with teeth marks in the same pattern and manner to those found on herbivorous dinosaurs in the same area. As there were no predators capable of challenging the domination of Majangasaurus on the island, these can only be the results of an act of cannibalism. This is the only non avian theropod dinosaur known to have resorted to this behavior and perfectly illustrates its ruthless resourcefulness it would have needed to to survive.
http://www.oldearth.org/curriculum/dinosaur/majungasaurus.jpg
http://www.oldearth.org/curriculum/dinosaur/majungasaurus.jpg
Science Uncovered - Dinosaurs Rediscovered.
Explore Magazine - Dinosaurs Undiscovered.
Explore Magazine - Dinosaurs Undiscovered.
Teeth shape.
The teeth of some tyrannosaurs may have been even more lethal than they originally appeared. It is now believed they may have been specially designed to trap scraps of flesh and subsequently provide ideal conditions for bacteria to breed. As a result of this even an initially non fatal bite could cause death within days as the wound would have turned gangrenous and failed to heal. Once the prey succumbed to its injuries, the predator would have been able to feed at its leisure.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
Defense.
Armour.
Think Armour and Ankylosaurus and Euoplocephalus immediately come to mind. The ankylosaurus when threatened with a predator had at least two defensive strategies. An ankylosaur could potentially position itself low to the group meaning the only way its vulnerable underbelly could have been attacked would be to flip it over. Perhaps its most iconic defensive strategy however was the club which has been found on the end of the tail. This would have been made as a result of fused vertebrae and tendons supported by bony deposits. Although we will never know for certain the amount of damage the club could cause to potential attackers, it is possible with enough force it could have broken the thickest dinosaur bones around. The use of armour was even employed sauropods which although was nowhere near the extent of the previously mentioned ankylosaurs, may still have helped to fend off attacks by packs of raptors.
Think Armour and Ankylosaurus and Euoplocephalus immediately come to mind. The ankylosaurus when threatened with a predator had at least two defensive strategies. An ankylosaur could potentially position itself low to the group meaning the only way its vulnerable underbelly could have been attacked would be to flip it over. Perhaps its most iconic defensive strategy however was the club which has been found on the end of the tail. This would have been made as a result of fused vertebrae and tendons supported by bony deposits. Although we will never know for certain the amount of damage the club could cause to potential attackers, it is possible with enough force it could have broken the thickest dinosaur bones around. The use of armour was even employed sauropods which although was nowhere near the extent of the previously mentioned ankylosaurs, may still have helped to fend off attacks by packs of raptors.
Stegosaurs also used armour in the form of a thagomizer- an arrangment of spikes found on the tail. The number and the direction the spikes pointed was species dependent. Evidence of the damage this weapon could inflict has been found as a result of puncture marks to the tail vertebrae of an allosaurus. It is not unusual for spike specimens to be found with evidence of heavy use implying they were employed on a regular basis. Scientists also believe stegosaurs may have flushed blood into their plates along their backs to intimidate predators.
http://upload.wikimedia.org/wikipedia/commons/3/33/Ankylosaurus_magniventris.jpg
Explore Magazine - Dinosaurs Undiscovered.
http://upload.wikimedia.org/wikipedia/commons/3/33/Ankylosaurus_magniventris.jpg
Explore Magazine - Dinosaurs Undiscovered.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
Tail.
The giants of the dinosaur world the sauropods moved in herds and would surely have been a sight to make any potential predator think twice about attacking. The enormous tails acted as a counter balance for their equally large necks and potentially to loose unwanted heat as a result of their large surface area. They may also have acted as an extra form of defense, with scientists speculating they could have been used as a whip to cause terrible injuries to attackers. Others have theorised the sound alone these tails could have caused by flicking their tails may have caused a noise travelling far and wide as a warning to dinosaurs with predatory intentions.
http://scienceline.org/wp-content/uploads/2013/02/1033477755_05a94f77e4_z-e1361769534208.jpg
Explore Magazine - Dinosaurs Undiscovered.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
The giants of the dinosaur world the sauropods moved in herds and would surely have been a sight to make any potential predator think twice about attacking. The enormous tails acted as a counter balance for their equally large necks and potentially to loose unwanted heat as a result of their large surface area. They may also have acted as an extra form of defense, with scientists speculating they could have been used as a whip to cause terrible injuries to attackers. Others have theorised the sound alone these tails could have caused by flicking their tails may have caused a noise travelling far and wide as a warning to dinosaurs with predatory intentions.
http://scienceline.org/wp-content/uploads/2013/02/1033477755_05a94f77e4_z-e1361769534208.jpg
Explore Magazine - Dinosaurs Undiscovered.
Camouflage.
Exams of camouflage in the modern day natural world are everywhere.
It is possible that camouflage was used as a defensive strategy for dinosaurs
as well. Striped hadrosaur skin has revealed at the very least their tails were
striped. Considering the difficulty stripes make identifying a prey animal
for predators in the modern world, it may not be unreasonable to theorise the
stripes may have covered the vast majority of the hadrosaurs body.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
Explore Magazine - Dinosaurs Undiscovered.
Vocalisation.
Crested skull hadrosaurs for example parasaurolophus, are
likely to have used vocalisations over large distances by bellowing and subsequently
warning the rest of its herd of imminent danger.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
Size.
For sauropods size alone would have made them almost immune from the threat of predation. The chances of reaching adulthood would have been slim however as the youngsters were very vulnerable. For example for every thirty eggs laid by a diplodocus, only one or two or youngsters would have survived to become an adult.
For sauropods size alone would have made them almost immune from the threat of predation. The chances of reaching adulthood would have been slim however as the youngsters were very vulnerable. For example for every thirty eggs laid by a diplodocus, only one or two or youngsters would have survived to become an adult.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
Quick growth rate.
Hypacrosaurus, with no natural defenses and the description of the Thompson's Gazelle of the Late Cretaceous, may well have been very vulnerable to an array of predators. The hadrosaur did however have one antipredation strategy which may have improved its chances of survival research has revealed. As a comparison of growth rates which were assessed by counting growth rings on sections of leg bones each ring accounting for one year of life. It was discovered the hadrosaur grew between three and five times faster than any potential predator living at the same time.
In the time it would have taken a tyrannosaur to become half grown, Hypacrosaurus would have been fully grown and as a result there would have been an enormous difference in size. As well as this the hadrosaur also reached sexual maturity early - typically between two and three years of age.
http://www.sciencedaily.com/releases/2008/08/080805192720.htm
Speed.
Running is possibly one of the simplest but also one of the most instinctive forms of defense in the face of danger. We know hadrosaurs were capable of making a hasty retreat on two legs and although ascertaining from the fossil record how fast a dinosaur could move is very tricky, comparisons can be made with modern day animals. Galliminus for example shares similar traits to ostriches including a long neck and muscular, powerful legs. Ostriches can run at speeds of up to 45 miles per hour and with Galliminus reaching up to eight metres in height, it may not be unreasonable to assume they could also reach similar speeds.
Explore Magazine - Dinosaurs Undiscovered.
http://dinosaurs.about.com/od/dailylifeofadinosaur/a/dinocombat_2.htm
Explore Magazine - Dinosaurs Undiscovered.
There is little doubt that world of dinosaurs would have been a harsh and unforgiving place where only the fittest survived. We are just lucky we have the evidence they left behind to give us an insight into their incredible world.
That is all for this time, as always I hope you enjoyed reading and all the best,
George.
Twitter @ReallyWildWykes
