Crocodilian & Elasmobranch interactions

[elosha11]

Interesting documentary that mentions it's very dangerous for subadult crocs to be swimming in waters with big bull sharks, and shows some interactions between the two. Here's some clips. It's interesting how much thicker the sharks are at comparable length, although of course, the male croc is a subadult and more gracile than he will be full grown.

[Ceratodromeus]

Here's another Alligator eating a bonnethead

[elosha11]

Jan 2, 2020 23:54:02 GMT 5 dinosauria101 said:

Little surprised this wasn't posted, but here's the GWS eating the American crocodile:
Carrier, Jeffrey C.; Musick, John A.; Heithaus, Michael R. (2012-04-09). Biology of Sharks and Their Relatives (Second ed.). CRC Press. ISBN 9781439839263.

Tiger sharks – which commonly patrol coastal waterways – could pose a threat to any croc, given their large size, robust serrated teeth (which can saw through a sea-turtle shell like nobody's business), and up-for-anything predatory habits. So could, of course, the more massive great white shark, which grows to similar lengths as Indo-Pacific or Nile crocodiles and can substantially outweigh them. There are records of white sharks preying on adult American crocodiles in the Columbian Caribbean.

www.earthtouchnews.com/natural-world/animal-behaviour/when-crocodiles-go-to-sea/

However, Great White Sharks (Carcharodon carcharias) prey upon adult C. acutus in Colombia (Medem,1981), and large sharks may kill subadult and adult crocodilians in other areas (Webb andMessel, 1977).

The Role of Predation in Shaping Crocodilian Natural History, Dec. 2013.

www.researchgate.net/publication/259450979_The_Role_of_Predation_in_Shaping_Crocodilian_Natural_History


Also this source quotes Medem more specifically, stating that white sharks fatally attacking adult American crocs off Isla Fuerte, Columbia, was "not uncommon in the past." See p. 254.

books.google.com/books?id=97oE6gTFW8EC&pg=PA28&lpg=PA28&dq=Medem,+F.+1981.+Los+crocodylia+de+Sur+America,Volume+1,+Los+Crocodylia+de+Colombia.+Colciencias,Colombia&source=bl&ots=f20qB3SpsH&sig=ACfU3U0R2odv26M4Oo6tQZcIe7Bvw_IW4g&hl=en&sa=X&ved=2ahUKEwjAlrXoh-7mAhXLdN8KHcU7DsoQ6AEwAnoECAYQAg#v=onepage&q=shark&f=false

[elosha11]

www.australiangeographic.com.au/news/2017/04/endangered-sawfish-battle-crocodiles-and-sharks/

Both bull sharks and crocs appear to prey on another shark-related elasmobrach, the sawfish.

[elosha11]

From www.researchgate.net/publication/319940305_Reciprocal_Intraguild_Predation_between_Alligator_mississippiensis_American_Alligator_and_Elasmobranchii_in_the_Southeastern_United_States. While documenting alligators taking sharks, as seen in other pics on this thread, it also says this about the opposite scenario.

Depredation and serious injury of other crocodilian species by Elasmobranchii are more frequently reported. Price (1877) described an altercation between what were likely Caiman crocodilus (L.) (Spectacled Caiman) and several sharks (un-identied species) in Manzanilla, Mexico. Like the events described in several accounts of American Alligator depredation, heavy rains had displaced a number of Spectacled Caiman from a coastal freshwater lake into a tidal river. Once in the river, the caiman were reportedly immediately attacked by sharks. Similar to ac-counts for alligators, a violent battle was said to last all day, though, in this case all Spectacled Caiman involved in the skirmish suffered mortality. In the July 1962
Southeastern NaturalistJ.C. Nifong and R.H. Lowers2017 Vol. 16, No. 3392issue of the periodical Louisiana Conservationist published by the Louisiana Wild-life and Fisheries Commission, the author of the article “What You Should Know about Sharks” describes several findings of crocodilian remains in the stomachs of large Galeocerdo cuvier (Péron and Lesueur) (Tiger Shark) captured in coastal waters of Indonesia and South Africa. Described therein, a Tiger Shark (~3 m TL) was captured somewhere off the coast of Indonesia with an entire Estuarine Crocodile (2 m TL) in its stomach. Similarly, off the coast of Durban, South Africa, a Tiger Shark (~4 m TL) contained the head and upper body portions of a Nile Crocodile along with the hind limbs of a Ovis aries L. (Domestic Sheep), 3 seagulls (unde-ned taxa), 2 cans of peas, and a cigarette tin. More recently, Somaweera et al. (2013) reported that hatchling and juvenile Estuarine Crocodiles as well as Fresh-water Crocodiles inhabting tidal rivers in northern Australia are consumed by Tiger Sharks, Carcharhinus amboinensis (Müller and Henle) (Pigeye Shark), and Glyphis spp. (river sharks) as well as a large predatory fish, Lates calcarifer (Bloch) (Bar-ramundi). Webb and Messel (1977) attributed numerous tail amputations observed in hatchling Estuarine Crocodiles to shark attacks. In addition, several web pages have published putative evidence for the predation of crocodiles by sharks. Nelson (2013) reported photographs and video detailing the discovery of the head of a Nile Crocodile (~3.5 m TL) on a beach in St. Lucia, South Africa. In light of the clean bite wound, apparent teeth marks, and the fact that poachers would have most certainly retained the skull as a trophy, it was postulated that only Carcharodon carcharias (L.) (Great White Shark) could have delivered such a mortal bite. In Columbia, Great White Sharks have been documented to prey upon adult American Crocodiles (Medem 1981), which attain similar body sizes to Nile Crocodiles. Both the Tiger Shark and Bull Shark (known crocodile predators) occur in coastal habitats frequented by American Alligators; these elasmobranchs can kill and consume crocodilians similar in body size to American Alligators. We suggest, stomach-content analysis of large-bodied individuals occurring sympatrically with American Alligators may help to assess the importance and prevalence of these interactions in the southeastern United States.

[Ceratodromeus]

Jan 10, 2020 4:30:06 GMT 5 elosha11 said:

From www.researchgate.net/publication/319940305_Reciprocal_Intraguild_Predation_between_Alligator_mississippiensis_American_Alligator_and_Elasmobranchii_in_the_Southeastern_United_States. While documenting alligators taking sharks, as seen in other pics on this thread, it also says this about the opposite scenario.

Depredation and serious injury of other crocodilian species by Elasmobranchii are more frequently reported. Price (1877) described an altercation between what were likely Caiman crocodilus (L.) (Spectacled Caiman) and several sharks (un-identied species) in Manzanilla, Mexico. Like the events described in several accounts of American Alligator depredation, heavy rains had displaced a number of Spectacled Caiman from a coastal freshwater lake into a tidal river. Once in the river, the caiman were reportedly immediately attacked by sharks. Similar to ac-counts for alligators, a violent battle was said to last all day, though, in this case all Spectacled Caiman involved in the skirmish suffered mortality. In the July 1962
Southeastern NaturalistJ.C. Nifong and R.H. Lowers2017 Vol. 16, No. 3392issue of the periodical Louisiana Conservationist published by the Louisiana Wild-life and Fisheries Commission, the author of the article “What You Should Know about Sharks” describes several findings of crocodilian remains in the stomachs of large Galeocerdo cuvier (Péron and Lesueur) (Tiger Shark) captured in coastal waters of Indonesia and South Africa. Described therein, a Tiger Shark (~3 m TL) was captured somewhere off the coast of Indonesia with an entire Estuarine Crocodile (2 m TL) in its stomach. Similarly, off the coast of Durban, South Africa, a Tiger Shark (~4 m TL) contained the head and upper body portions of a Nile Crocodile along with the hind limbs of a Ovis aries L. (Domestic Sheep), 3 seagulls (unde-ned taxa), 2 cans of peas, and a cigarette tin. More recently, Somaweera et al. (2013) reported that hatchling and juvenile Estuarine Crocodiles as well as Fresh-water Crocodiles inhabting tidal rivers in northern Australia are consumed by Tiger Sharks, Carcharhinus amboinensis (Müller and Henle) (Pigeye Shark), and Glyphis spp. (river sharks) as well as a large predatory fish, Lates calcarifer (Bloch) (Bar-ramundi). Webb and Messel (1977) attributed numerous tail amputations observed in hatchling Estuarine Crocodiles to shark attacks. In addition, several web pages have published putative evidence for the predation of crocodiles by sharks. Nelson (2013) reported photographs and video detailing the discovery of the head of a Nile Crocodile (~3.5 m TL) on a beach in St. Lucia, South Africa. In light of the clean bite wound, apparent teeth marks, and the fact that poachers would have most certainly retained the skull as a trophy, it was postulated that only Carcharodon carcharias (L.) (Great White Shark) could have delivered such a mortal bite. In Columbia, Great White Sharks have been documented to prey upon adult American Crocodiles (Medem 1981), which attain similar body sizes to Nile Crocodiles. Both the Tiger Shark and Bull Shark (known crocodile predators) occur in coastal habitats frequented by American Alligators; these elasmobranchs can kill and consume crocodilians similar in body size to American Alligators. We suggest, stomach-content analysis of large-bodied individuals occurring sympatrically with American Alligators may help to assess the importance and prevalence of these interactions in the southeastern United States.

that section is in the OP, it's a shame there weren't more photographs to go along with that section though. The stomach content analysis line makes me want to see if there's any research that they might have missed that would show alligator remains in shark stomachs

[Ceratodromeus]

Much like the video of the bull shark response to American crocodile pheromones, Here is a small section regarding lemon shark reaction to C.acutus pheromones


From: Biology of sharks and their relatives


There is an interesting line about how water from alligator ponds elicited no reaction from lemon sharks, and while this was published before the study showing depredation of lemon sharks by Alligators, it would be interesting to see this done again.

---

Here is the referenced material from Rasmussen and Schmidt (1992)<sup>{1}




Reference
{1} Rasmussen, L. E. L., and Michael J. Schmidt. "Are sharks chemically aware of crocodiles?." Chemical Signals in Vertebrates 6. Springer, Boston, MA, 1992. 335-342.</sup>

[Ceratodromeus]

Another crocodile-shark interaction documetary, Here is Saltwater crocodile interactions with lemon sharks.

[Bujang Senang]

Jan 3, 2020 22:19:05 GMT 5 elosha11 said:

One can make of this what they will. Some think it was poachers, but poachers would not leave the valuable head of a croc. A carnivora posters I debated previously claimed it as a boat propeller (he was a definite croc fanatic) and showed a picture from facebook of what he claimed was the rest of the croc's body in the surf, but the picture was obscure and showed the croc from behind, without even any indication that the croc was missing its head. Also he claimed it was reported in the news that the croc's remaining body was found and that it was a clear boat accident, but he failed to provide any sources for this, and he proved very ready to believe/promote fake sources as long as it benefited the crocodile. I also note that most boating propellers that kill animals leave much more mutilated and messy corpses than this, as the propeller strikes the animal multiple times, not a clean slice mark like this.

Some say the person who found the head said it showed teeth marks of the shark, and the point of the video where I have it marked show him showing a flap of cut skin above the decapitation that could be a cut caused by a large shark tooth. But it could also be made by some other source. We can't eliminate poaching, boat, or shark. I'd say it's possible a large great white or tiger could do this to a 3.5 meter croc. Whether that's what really occurred and whether it was a predation or a scavenging is unknown.

There is no reason to think that a large great white shark was involved in the death of this Nile croc, especially considering observations from Ezemvelo staff. However, they concluded poaching, not a boat propeller:

In spite of a shark being blamed earlier for decapitating an estimated 3.5m crocodile at St Lucia (https://www.2oceansvibe.com/2013/01/14/shark-blamed-for-decapitated-crocodile-head-washing-up-on-st-lucia-beach-video/), it was later discovered by Ezemvelo staff that it was more likely to be a victim of a poaching incident.

Suggestions were also made that it may have been a hippo, until staff turned over the remains of the head of the croc, it was apparent that the tongue was missing. It was clear that someone had used a sharp object to cut it underneath to remove the tongue. Further south, towards the Mfolozi mouth, two other pieces of the croc were also discovered. It was strongly believed that these belonged to the same head that had been found initially.

The crocodile is estimated to have been dead for about 3-4 days judging by the carcass smell, and the evidence of maggots on the head. It should therefore be noted that suggestions of a giant Great White are unfounded. However, it also suggests that the fight against poaching is not only limited to Rhino, and in some areas elephant. Other species such as Oribi, vultures, cycads, orchids and many others are poached, and more often than not persecuted. It is Ezemvelo's hope that poaching on a larger scale will be highlighted, and that the nation as a whole, who are charged with conserving biodiversity, would learn the value of biodiversity, and the provision of ecosystem services that we freely enjoy.

www.facebook.com/EzemveloKZNWildlife/photos/a.286061221414399/519962844690901/?type=3

[Bujang Senang]

Nile crocodile attacks a bull shark:



Saltwater crocodile attacks a lemon shark:


Other interactions of the same saltie with lemon sharks:



Saltwater crocodile with a juvenile bull shark:









5 m saltwater croc eating a bull shark in Kakadu National Park:



Old news account describing a 10 foot saltwater crocodile killing a 7 foot shark of unknown species (may be bull or sand tiger):

And the opposite old news account describing a 10 foot (bull?) shark killing a 7-foot American alligator:


Description of a fight between a 8 foot crocodile and some "very large" shark from old George Dawson Flinter book "A History of the Revolution of Carácas":


Sand tiger/Bull shark killed and cached by saltwater crocodile:



Observation from "Surveys of Tidal River Systems in the Northern Territory of Australia and Their Crocodile Populations" book:

Shark capture by large crocodile. At 1405 hrs (90 minutes after high tide) on September 20, 1 977, a crocodile >11ft in length was observed floating downstream past the anchored vessel at km32. The crocodile's movements were observed with the help of binoculars. After passing the vessel, the crocodile's head was observed to go quickly underwater and come up with a 3-4 ft shark (probably a freshwater whaler). The crocodile then submerged its head with the shark in its mouth, but its back remained visibly arched out of the water.

16 foot great white shark contained 4-5 foot australian freshwater crocodile in the stomach, data from book "Population Dynamics of Crocodylus Porosus and Status, Management and Recovery: Update 1979-1983":

[Bujang Senang]

Some photos of crocs and sharks without interactions or descriptions of interactions:

[Bujang Senang]

Jan 6, 2020 8:58:30 GMT 5 elosha11 said:

Jan 2, 2020 23:54:02 GMT 5 dinosauria101 said:

Little surprised this wasn't posted, but here's the GWS eating the American crocodile:
Carrier, Jeffrey C.; Musick, John A.; Heithaus, Michael R. (2012-04-09). Biology of Sharks and Their Relatives (Second ed.). CRC Press. ISBN 9781439839263.

Tiger sharks – which commonly patrol coastal waterways – could pose a threat to any croc, given their large size, robust serrated teeth (which can saw through a sea-turtle shell like nobody's business), and up-for-anything predatory habits. So could, of course, the more massive great white shark, which grows to similar lengths as Indo-Pacific or Nile crocodiles and can substantially outweigh them. There are records of white sharks preying on adult American crocodiles in the Columbian Caribbean.

www.earthtouchnews.com/natural-world/animal-behaviour/when-crocodiles-go-to-sea/

However, Great White Sharks (Carcharodon carcharias) prey upon adult C. acutus in Colombia (Medem,1981), and large sharks may kill subadult and adult crocodilians in other areas (Webb andMessel, 1977).

The Role of Predation in Shaping Crocodilian Natural History, Dec. 2013.

www.researchgate.net/publication/259450979_The_Role_of_Predation_in_Shaping_Crocodilian_Natural_History


Also this source quotes Medem more specifically, stating that white sharks fatally attacking adult American crocs off Isla Fuerte, Columbia, was "not uncommon in the past." See p. 254.

books.google.com/books?id=97oE6gTFW8EC&pg=PA28&lpg=PA28&dq=Medem,+F.+1981.+Los+crocodylia+de+Sur+America,Volume+1,+Los+Crocodylia+de+Colombia.+Colciencias,Colombia&source=bl&ots=f20qB3SpsH&sig=ACfU3U0R2odv26M4Oo6tQZcIe7Bvw_IW4g&hl=en&sa=X&ved=2ahUKEwjAlrXoh-7mAhXLdN8KHcU7DsoQ6AEwAnoECAYQAg#v=onepage&q=shark&f=false

Maybe it's better to just quote the original source, rather than different interpretations of it?


This text needs to be translated, however, immediately clear that Medem did not wrote that the American crocodiles attacked by great white shark near Fuerte island were adults. He even did not say that crocs were killed, only that the attacking sharks did not allow them to swim from the island to mainland or vice versa.

[elosha11]

From Google Translate: Note that Medem states the GWS and several other shark species are enemies of the adult American crocodile. It's a pretty easy inference to believe that inhabitants observed white sharks attacks on adult crocs, along with probably juveniles.

Again, this simply shows the typical shark/croc interaction, the larger animal dominates and may prey on the smaller one.


"The only natural enemies of adult crocodiles are the "tiger" (Pantheru onca) and several tiburones, espccially the "white shark" (Car charodon carcharias, Isuridae), which abounds around Isla Fuerte. On May 5, 1955, a 230 cm long one was found at night and already in an advanced state of decomposition, in the bay of the Pto. Limon farmhouse located to the east of this island. His belly was about 30 cm wide. the intestines, part of the flanks and the right hind limb were missing, while the rest of the body, including the cranc, has been left. (CNHM 74923), it was intact. According to the inhabitants, it was quite common for white sharks to attack crocodiles in the sea, between 20 and 200 meters from the coast, and that this reason, they could not migrate to the mainland (8 km) or vice versa."

[dinosauria101]

elosha11

If I'm reading that right, GWS are commonly known to kill American crocs?

[elosha11]

Apparently, it was somewhat common in the 50's. I've heard GWS are relatively rare there now, probably for a variety of environmental and natural factors. So I doubt it's common now.