Wednesday, October 11, 2017

Killer Tooth Ache


Statements compiled & composed by Dr Ingrid Visser 

Anyone with a tooth ache knows how painful and distracting that can be. For an orca (killer whale), which has around 48 large teeth, a sore tooth is likely no less painful or debilitating than for a person. A new study, investigating teeth of captive orca, found that every individual studied had damaged teeth.

Dr John Jett, an ex-orca trainer, now professor and first author on the paper says, “We investigated 29 orca owned by one company and held in the USA and Spain. Every whale had some form of damage to its teeth. We found that more than 65% possessed moderate to extreme tooth wear in their lower jaws, mostly as a result of chewing concrete and steel tank surfaces.” 

Drs John Jett & Ingrid Visser 
Additionally, the researchers found that more than 61% of the orca have ‘been to the dentist’ to have their teeth drilled. Officially termed a ‘modified pulpotomy’, a hole is drilled into the tooth to extract the soft pulpy tissue inside. But unlike us, the resultant hole is not filled or capped, but rather is left open for the rest of the animal’s life, requiring daily flushing with chemicals to keep the teeth empty of food and bacteria in an attempt to manage ensuing infection. 

Dr Loch At the Muséum national d'Histoire naturelle
Dr Carolina Loch, a scientist who specializes in the dentition of whales and dolphins and a co-author, explained that once the tooth gets worn to the point where the pulp is exposed, “this opens up a channel for disease and infection, so the staff then drill the teeth.” 

Dr Jeffrey Ventre another of the authors, who is also an ex-orca trainer and now a medical doctor stated that he had drilled orca teeth and that "teeth damage is the most tragic consequence of captivity, as it not only causes morbidity and mortality in captive orcas, but often leads to chronic antibiotic therapy compromising the whale's immune system, as we saw recently with the orca known as Kasatka.”

Loch added that “A drilled tooth is severely weakened and if any other trauma occurs, fractures will happen. We have documented more than 60% of the second and third teeth of the lower jaws were broken and this high number is likely linked to the drilling.” During his time as a trainer, Ventre said that he had witnessed "whales breaking their teeth on steel gates while jaw popping. Small tooth fragments were then collected below the gate while diving the pool."

An investigative researcher and co-author noted that “the damage to the teeth of these animals is so severe that most individuals can be identified by the specific fractures and tooth wear alone, much like forensic pathologists use for identification of
humans post-mortem.”

Ventre noted that “The obligatory daily teeth irrigations render the compromised orcas poor candidates for full release”, should companies ever make the transition to look at rehabilitation for their captives.

Dr Ingrid Visser with Samantha Berg at Superpod 2 
Dr Ingrid Visser, a scientist who has studied orca in the wild for more than three decades and has long been advocating for an end to orca captivity, stated that “We know that confining them in tanks is bad for the animals and this research now gives us some hard numbers to illustrate just how their health and welfare is compromised. Given how big the root of an orca’s tooth is and that orca have a nervous system similar to ours, these injuries must be extremely painful.” 

She is a co-author for this study and noted that compared to free-ranging orca, “the teeth of captive orca are incredibly compromised and you just don’t see this type or level of damage in the wild.”

Drs Ventre & Jett August 2017, Image Mariah Kirby 
Loch pointed out that “dentists have long said that oral health is a measure of general health as our mouths are the gateway to our body”, and she believes that this is likely the same for orca. Jett concluded “We have documented that tooth damage starts at a very early age in captivity and that all the orca in the study have issues with their teeth. Teeth are incredibly important to the overall health of an animal, and the results of our study should raise serious concerns for the health and welfare of captive orca.”

Author contact details, Study Highlights and Citation details are given below. 


The authors can be contacted on: (J. Jett); (J. Ventre); (C. Loch), (I. Visser);

Study Highlights:

1)  Using high-resolution photographs, individual teeth in the mandible and maxilla of captive orca were scored for coronal wear, wear at or below the gum line, fractures, bore holes and missing.

2)  Dental damage was commonly observed across all captive whale cohorts, with damage beginning early in a whale’s captive life.

3)  Forty five percent of whales exhibited “moderate” mean mandibular coronal wear, and an additional 24% exhibited “major” to “extreme” wear.

4)  More than 61% of mandibular teeth 2 and 3, and 47% of mandibular tooth 4, exhibited evidence of having undergone the ‘modified pulpotomy’ procedure.

5)  Conspecific aggression and oral stereotypies such as biting on hard tank surfaces likely contributed to the tooth pathology observed.

Study Citation details:

John Jett, Ingrid N. Visser, Jeffrey Ventre, Jordan Waltz, Carolina Loch, Tooth Damage in Captive Orcas (Orcinus orca), Archives of Oral Biology, Available online 29 September 2017, ISSN 0003-9969,