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Biology 4663: Advanced Elasmobranch Studies > Topic 6: Bite Forensics > Flashcards

Topic 6: Bite Forensics Flashcards

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1
Q

Hit and run (_%) of attacks and in ___ waters. Speculate many involved are ___ sharks.

A

80%
shallow
juvenile

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2
Q

Sneak attacks come out of ____ and are usually in ___ water.

A
  • the blue

- deep

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3
Q

Bump and bite is when sharks??

A
  • bump the victim first (assessing potential meal?Exploratory?Threat?); deeper water as well!! Intentional feeding..
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4
Q

Why is it safe to assume that not all shark attacks are feeding behaviour?

A
  • if they were…there would not be as many of survivors!
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5
Q

Explain non-aggressive and aggressive behaviour indicators in sharks. (mostly documented with a blacktip reef shark)

A
  • Aggressive behaviour: very over exaggerated movement…arched body.. tail is way out…very bizarre types of behaviour instead of swimming horizontally… pectoral fins going straight down! (launch attack indicator?) Moving head side to side!
  • Non-aggressive behaviour: pectoral fins are roughly horizontal…tips of tail moving are to exaggerated
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6
Q

Pathology of Shark Attack:

- Traumatic effects are dependent on ___ and ___.

A

-species and size

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7
Q

Pathology of Shark Attack:

- Lower teeth ____ while upper jaw is ??

A
  • fix prey

- protruded and head shaking or rolling(to remove chunks)

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8
Q

Pathology of Shark Attack:

-Hit and run usually involves injuries where?

A
  • extremities
  • 70% lower limb only (surfers etc)
  • upper injured trying to fend off attacker
  • slashing by shark results in linear lacerations
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9
Q

Pathology of Shark Attack:

- Usually if people die its because of??

A
  • the sheer trauma or because people on site do not know what they are doing in terms of medical care…Dangerous place: lower limbs…venus flows…other spurts
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10
Q

Pathology of Shark Attack:
- Durban classification of prognosis following shark attack, according to wound type.
L> Grade of injury, description and outcome?

A

I. Both femoral arteries; or one femoral artery and one posterior tibial; or one femoral artery in upper 1/3…..outcome: often fatal
II. One femoral artery in lower 2/3; one brachial artery; two posterior tibias; abdominal wounds with bowel involvement(major)…..outcome: should survive, with appropriate pre hospital treatment
III. One posterior tibial; superficial limb wounds; no vessels cut; superficial abdominal wounds; with no peritoneal involvement; both forearm vessels….outcome: Always survive with appropriate pre-hospital treatment!

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11
Q

Pathology of Shark Attack:

-Bumping can cause serious ______, can form long______.

A
  • abrasions (in a larger shark and if its coming at a high speed…due to the dermal denticles on the sharks body)
  • deep grooves in skin and underlying tissue
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12
Q

Pathology of Shark Attack:

-Wounds depend on degree of?

A
  • dental serration
  • finer tooth: sharp wound edges
    L> nice smooth crescent shaped bite marks (GW and tiger)..shake head!
  • coarse or minimal dental serration: deeper puncture and ragged edges!
    L> not a nice clean cut! ..bigger gaps in serrations on teeth= more jagged wounds….
    -longer more dagger shaped teeth bite down much deeper vs serrated ones because they do not have to bite as deep…they can just take off a huge chunk cleanly.
  • long and jagged= mako…. not a nice clean cut!
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13
Q

Pathology of Shark Attack:

- Many shark bites become??

A
  • infected
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14
Q

Pathology of Shark Attack:
-Many shark bites become infected. Many ___ bacteria!
L> what is the main one in sharks?

A
  • atypical
  • Halophilic: can cause rapid cellultitis (skin infection or myositis (inflammation of muscles ) within hours. (has a very quick infection rate…some people die days after bc antibiotics do not take effect)
  • *sharks mouth is filled with bacteria
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15
Q

Pathology of Shark Attack:

- Many shark bites become infected.Many atypical bacteria. Vibrio spp??

A
  • gram-negative
  • causes septicemia (whole body inflammation) now called systemic inflammatory response syndrome (SIRS)
    L> basically the whole body is acting towards the infection and the rest of the body is shutting down in the process…people get this from uncooked seafood as well!
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16
Q

Pathology of Shark Attack:
- Treatment
L>main symptoms??

A
  • extreme exhaustion
  • severe haemorrhage
  • hypothermic (body temp is dropping)
  • near-drowned (lungs are probably filled with a lot of salt water
  • *loss of a lot of blood!
  • *ONLY remove from surf zone..so you are not being pounded by waves while working
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17
Q

Pathology of Shark Attack:
- Treatment
L>priorities are to??

A
  • secure airway
  • control haemorrhage
  • resuscitation and rewarm (if body temp isn’t kept up…a whole cascade of problems can occur!)
18
Q 
Pathology of Shark Attack:
- Treatment
L> Direct pressure??
L> Tourniquets?
L>Look for signs of?
A
  • on wounds
  • they are controversial due to the fact that they completely restrict blood flow but may be necessary! (since blood flow is completely restricted …you could lose a limb)
  • signs of shock: dizziness, incoherence, lethargy leading to unconsciousness
19
Q

Pathology of Shark Attack:
- Treatment
L>when does shock occur?

A
  • after trauma..it is a cascade effect in the body form blood loss and fluid loss…the body tries to compensate for it! Bp drops a lot..body increases heart rate to get more blood flow to the body…dilate which then causes bp to go down further…increase dilation more…bp goes down entirely…body goes into shock!
20
Q

Pathology of Shark Attack:
- Treatment
L>keep blood flow in___area
L> lift up?

A
  • core

- lower limbs

21
Q

Pathology of Shark Attack:
- Treatment
L>what can happen when a lower limb is completely taken during an attack?

A
  • the body will constrict the femoral artery completely which can sae an individual…blood flow becomes just a trickle
22
Q

Video:

  • Fatal attacks are very rare/common
  • each species of shark creates a similar/unique bite pattern.
  • gaps between teeth act as?
A
  • rare
    -unique
    L> Serrated and close together = tiger
    L> big gaps between teeth…upper jaw (GW)
    **gap between teeth= indicator of the type of shark that has attacked…from bite forensics…it can give possible suspects but cannot ensure anything!
23
Q

Great white relaxed ands attack jaw states…explain!

A
  • when relaxed: hyoid arch is relaxed (almost an L shaped bend) when jaws are retracted
  • when jaws are protruding (attacking): hyoid arch is in rotated position bracing the jaw (almost a straight shape)
  • When palatoquadrate is protruded, skin behind the eye which is attached directly to underlying muscle is pulled tight over postorbital process causing eye hump! (when not biting it goes away)
24
Q

Imprint of upper teeth; ____ spaced and ___ and ___.

Imprint of lower teeth, punctures are ____ in ____ and ___.

A
  • regularly…broad…flattened
  • less regular in spacing and distribution
  • *aka….not just the tooth in the imprint…it sunk all the way in..so base as well therefore there is much more space in between teeth than what is seen in an imprint from a shark attack… (identification = harder)
25
Q

How do you get a rough estimate of the size of a great white?

A
  • use anterior tooth
  • length of tooth indicates length of shark….measure it on an angle and multiply it by ten and you get a rough estimate!
26
Q

Shark bites on soft objects typically leave?

A

jagged edged roughly parallel lacerations

27
Q

Shark bites on hard objects typically leave??

A
  • a series of roughly parallel scratches or dents
28
Q

What are some ways we discussed in class to avoid shark attacks?

A
  • avoid contrasting colours on suits etc
  • don’t swim during dawn/dusk= foraging times (more active) of sharks…. lack of light = harder to see them
  • don’t swim where there is a high population of seals and other marine mammals
  • do not swim alone!!** someone else might get attacked instead if you are in large groups!(stats=in your favour more)
  • do not pee in the water
  • do not go into the water with open wounds…aka bleeding! (no blood!!) … if you do this may increase their curiosity….they can however tell the difference between fish blood and human blood…studies have been done and they go for the fish blood .. Sharks are very attuned to very minute traces of blood and can trace it well.
  • avoid murky water- a lot of people are attacked in it
  • no thrashing in the wage r
  • no shiny objects…they will attract sharks…sunlight can reflect off of it and maybe it seems like a fish scale to the shark!
  • avoid areas where people are fishing because it attracts sharks
  • obviously just don’t go into the water!
29
Q

Biologists are called upon to estimate shark __ and __ from investigation of bite wounds or damage. What is having reliable estimates key for?

A
  • size
  • species
  • *having reliable estimates key in understanding feeding and hunting behaviour and assessments of potential hazards for humans.
30
Q

Are there standardized forensic methods? What are they based on?

A
  • NOPE
  • based on investigator experience, geographic distribution of species(key since only certain species will reside in certain areas..narrows search), size range of particular species and matching wounds to dried jaws in museums!
31
Q

Orcas prey on?

A

bowhead whales

32
Q

Orcas prey on bowhead whales:

- IDD?

A
  • interdental distance - distance from the tip of one tooth to the next! (tested on orcas)
    L> consistent and different from other predators
    L> may hold true for sharks and of course show difference between upper and lower a jaw
    L> can be used as assessment of shark position relative to prey!
33
Q

Belugas harass bowhead whales but ??

A
  • IDD too small to account for rake marks found on them
  • study thought beulgas were hunting orcas…but this states not so much..Turnbull says that this would not be normal at all!
34
Q

Tooth size is related to?

A
  • total length in many shark species as is IDD
35
Q

With predictable relationship between IDD and shark total length and?????
L>Study example?

A
  • bite circumference as well..could establish the minimum size of the shark and help narrow candidate species
  • Study:
    L> white sharks, mako and 11 carcharhiniforms (tiger, bull, blacktip, lemon etc)
    L> used 10-24 jaws per species
36
Q

Describe figure 2 which is using the method involving IDD and circumference for length estimates!

A
  • Oblique anterior view of a cleaned and prepared bull shark lower jaw depicting the measurement of interdental distance (IDD..short line) and bite circumference (BC long line). Bite circumference is slightly larger than the summation of all IDD measures in a jaw because it is measured along the tooth bases. IDD was measured between the most labial teeth of the first size tooth files on each side of the symphysis, excluding the symphyseal teeth (if present). S symphyseal tooth. Numbers indicate tooth position counting from the symphysis.
37
Q

The arc of curvature of the bite circumference in the study was not measured for what two reasons?

A
  1. the dried position of the jaws was often anatomically incorrect
  2. this measurement is known to change during biting due to torsion of the jaw cartilages in at least some shark species
38
Q

In the study examining bite circumference and IDD….Two average IDD per jaw were calculated one for ___ and __ and used what kind of test to see if there was a statistical difference?

A
  • upper and lower
  • t-test
  • If no different all IDD averaged for species
  • then compared to total length of species
  • If different between upper and lower, done separately with length
39
Q

In the study examining bite circumference and IDD it also looked at the effect of ___ if dried out.

A
  • jaw shrinkage

- took rest jaws and measured IDD then dried them out and remeasured

40
Q

What were the major findings of the study examining bite circumference and IDD?

A
  • shark size and shark species may be determined by a few easily collected measurements
  • substantial overlap exists among the IDD and bite circumference but can be used to eliminate certain species during investigation
  • bite circumference is not reliable as perhaps angle of attack or use of only portion of jaw
41
Q

In the study examining bite circumference and IDD why may the methods have been compromised?

A
  • soft tissue deforms when bitten. rebounds when released and knits back together dependent on age; mechanical loading in the vicinity of the wound; multiple bites
  • materials degrade over time
    L> should be measured as soon as possible (IDD)
42
Q

Case Study:

  • Attack in Hawaii attributed to __ shark believed to be about __ m long.
  • Measured bite circumference to be? and put it into _____. Finding?
A
  • tiger
  • 4.5
    -645m = log 2.810
    -regression equation
    L> y= 1.085x-1.153
    L> found length to be 4.5m

Biology 4663: Advanced Elasmobranch Studies (11 decks)

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