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A total of 206 bone specimens were recognized as black rat (Rattus rattus) and two small tibiae were identified as belonging to the common house mouse (Mus musculus L.). Table VII. provides a summary of the identified bones.
Fig. 46. Analysis of these rat bones has revealed population size and makeup, evidence of cannibalism, and abnormal skeletal pathology.
Like the other faunal material, preservation of the rodent material is very good, though certain of the more fragile specimens (crania and vertebral spinous processes) have suffered some damage in antiquity (Armitage 1995a:2). Identification of rodent specimens was undertaken using Dr. Armitage’s modern comparative collections of rat skeletons (British and North American) and those of The Natural History Museum in London, England and Booth Museum of Natural History, Brighton, East Sussex, England. Determination of species was based on three primary diagnostic criteria: appearance of the temporal ridges of the neurocranium, mandibular diastema shape, and anatomical features of postcranial elements (Armitage 1995a:5).
| Bone element | No. of specimens N |
No. of elements NISP |
Minimum no. of individuals MNI |
|---|---|---|---|
* Adapted from Armitage 1995. | |||
| HEAD | |||
| cranium | 21 | indeterminate | indeterminate |
| mandible | 13 | 14 | 14 |
| isolated teeth | 15 | 15 | indeterminate |
| FORELIMB | |||
| scapula | 5 | 5 | 5 |
| humerus | 13 | 12 | 11 |
| radius | 5 | 5 | 5 |
| ulna | 6 | 6 | 6 |
| HINDLIMB | |||
| innominate bone | 11 | 11 | 10 |
| femur | 21 | 21 | 19 |
| tibia | 24 | 23 | 21 |
| EXTREMITY | |||
| metapodial bone | 4 | 4 | indeterminate |
| AXIAL | |||
| vertebrae** | 43 | 43 | indeterminate |
| sacrum | 14 | indeterminate | indeterminate |
| RIBS | |||
| rib | 11 | 11 | indeterminate |
| Total no. of specimens = 206 | |||
Osteological Analysis
Based on the stages of epiphyseal fusion as seen in the humerus, innominate, femur, and tibia specimens, a range of age classes was recognized: newborn, very young, young, young/subadult, subadult/adult, and indeterminate. A MNI (minimum number of individuals) count of 21 was calculated from the totals of unpaired and paired skeletal elements (Armitage 1995a:6,23). Sex was distinguished by
morphological criteria of innominate bones and by comparison with modern specimens of known gender. Two males and a female were identified.
Fig. 47. Drawing of rat skeleton showing outlines of bones recovered.
Oral Pathology
Analysis of mandible and maxilla specimens revealed ancient evidence of moderate to severe abscesses and infections in the rat population (Armitage 1995a:19). In several specimens the teeth had fallen out partially or entirely due to the loosening of their roots from swelling of the alveoli (teeth sockets). Whether their actual loss took place antemortem or postmortem (postdeposition) can not be determined.
Rickets
Fig. 48. Black rat tibiae. Healthy, modern specimen (right), compared with specimen (00,401.2) from the Emanuel Point Ship (left) showing pathological changes suggestive of rickets. Both are immature specimens. Drawings by Kate Armitage.
During the examination of the rodent material, it was noticed that six limb bones, “all from very young (immature) rats, are noticeably stunted (i.e., abnormally shortened) and have a distinctive, abnormally “flaring”or ”cup-like” outgrowth of the end of the shaft; either proximally or distally, depending on the type of skeletal element involved (Armitage 1995a:20).” These pathological changes are typically associated with rickets, as discussed by Baker and Brothwell (1980:49).
Cannibalism
One black rat tibia exhibited numerous shallow grooves over its surface. According to Armitage (1995a:23), these depressions were made by rodent incisor teeth indicating that the specimen had been gnawed by another rat or rats. Similar markings were found also found on the non-rodent faunal material (see above).
House Mice
Two left tibiae of the house mouse were found intermixed among the other faunal material. Mus musculus L., or more properly, Mus domesticus, is the European house mouse (Armitage 1995b:1; Berry 1981:92).
Fig. 49. Unexpected, considering the large population of rats on board, two left mouse tibiae were found intermixed with other rodent remains.
Armitage considered “the finding of two or more mice” aboard the ship as “unexpected” considering the large black rat population (Armitage 1995b:1). According to Berry (1981: 93, 111 &113), “mice are certainly predated by rats . . . and “infestation [of buildings, and presumably ships] by rats keeps down mouse numbers to some extent, but situations where rats can live usually provide conditions for a large population of mice.”
Discussion
“As contemporary sources reveal, rats were commonplace on European sailing ships voyaging to the New World in the 16th and later centuries. In modest numbers these vermin were merely a nuisance to mariners; the greatest damage done by them on ships resulted from the gnawing into the casks of stored foodstuffs and contaminating the contents within with their urine and feces. Under exceptional circumstances, however, their depredations of the ship’s provisions could represent a very real danger to the well-being and even survival of the crew and passengers” (Armitage 1995a:23). A rat plague besieged the returning Spanish Indies fleet of 1622 and on one vessel alone several thousand rats were caught and killed both in port and during the voyage (Phillips 1986:157).
An analysis of rat remains from the Emanuel Point ship has identified all the specimens aboard as the species, Rattus rattus, commonly known as the black rat. As for the population size of the rats on board, several factors make an accurate estimate impossible.
Bone remains found at the wrecksite account for a minimum of 21 individuals, probably far fewer than the total population prior to the vessel’s sinking. It seems most likely that many of the rodents would have tried to swim to shore at the time of sinking, some perhaps drowning at the site. However, the remains found at the site should not be assumed to have perished at the time of sinking.
Previous studies have shown that ships typically supported a population of animals that spent their entire lives aboard, from birth to death—meaning that some of the remains could have been the result of natural mortality perhaps preceding the time of the ship’s demise. Others might have been merely unlucky passengers taken aboard with provisions.
“Analysis does reveal, however, that there must have been a well-established, core rodent-population on the ship, as evidenced by the presence of very young, subadult, and mature individuals, and both males and females” (Armitage 1995a:24). Confinement in the “dark recesses of the ship’s hull, away from the sunlight, and with a restricted diet (probably lacking in certain minerals and vitamins essential for normal metabolism/growth) clearly took its toll on some of these rats, especially the immature individuals, as evidenced by the limb bones afflicted by rickets, and by the poor dental health of some of the older individuals.”
Class |
Order |
Taxon |
Element |
No. of Specimens |
|---|---|---|---|---|
Vertebrata |
indeterminate |
indeterminate |
fragments |
4 |
Vertebrata |
indeterminate |
small indet. |
long bone |
1 |
Vertebrata |
indeterminate |
medium indet. |
rib fragment |
1 |
Vertebrata |
indeterminate |
medium indet. |
rib fragment |
|
Vertebrata |
indeterminate |
medium indet. |
fragment |
1 |
Mammalia |
indeterminate |
very large indeterminate |
rib shaft fragment |
6 |
Mammalia |
indeterminate |
large/very large indeterminate |
fragment |
3 |
Mammalia |
indeterminate |
large indeterminate |
rib fragment |
1 |
Mammalia |
indeterminate |
large indeterminate |
long bone shaft fragment |
3 |
Mammalia |
indeterminate |
large indeterminate |
flat bone fragment |
1 |
Mammalia |
indeterminate |
medium indeterminate |
rib fragment |
1 |
Mammalia |
indeterminate |
med./large indeterminate |
epiphysis indeterminate |
1 |
Mammalia |
indeterminate |
med./large indeterminate |
pisiform |
1 |
Mammalia |
indeterminate |
med./large indeterminate |
fragments |
10 |
Mammalia |
indeterminate |
med./large indeterminate |
long bone shaft fragment |
1 |
Mammalia |
Artiodactyla |
small indeterminate |
condyle |
1 |
Mammalia |
Artiodactyla |
medium indeterminate |
lumbar vertebra |
1 |
Mammalia |
Artiodactyla |
Sus scrofa |
rib fragment |
1 |
Mammalia |
Artiodactyla |
Sus scrofa |
humerus |
2 |
Mammalia |
Artiodactyla |
Sus scrofa |
tibia |
2 |
Mammalia |
Artiodactyla |
Sus scrofa |
lower tooth PM3 |
1 |
Mammalia |
Artiodactyla |
Sus indet. |
scapula fragment |
1 |
Mammalia |
Artiodactyla |
Bovidae sp. |
rib fragment |
1 |
Mammalia |
Artiodactyla |
Bovidae c.f. Bos taurus |
ribs, vertebral end |
4 |
Mammalia |
Artiodactyla |
Bovidae c.f. Bos taurus |
rib epiphysis |
1 |
Mammalia |
Artiodactyla |
Bovidae c.f. Bos taurus |
thoracic vertebra |
2 |
Mammalia |
Rodentia |
Rattus rattus |
See Table VII |
206 |
Mammalia |
Rodentia |
Mus musculus |
tibia |
2 |
Aves |
Galliformes |
Gallus gallus |
tibia |
2 |
Aves |
Galliformes |
Gallus gallus |
ulna |
1 |
Aves |
Galliformes |
Gallus gallus |
femur |
1 |
Aves |
Galliformes |
Gallus gallus |
tarsometatasus |
1 |
Aves |
Galliformes |
Gallus gallus |
humerus |
1 |
Aves |
Galliformes |
Gallus gallus |
coracoid |
1 |
Aves |
Galliformes |
Gallus gallus |
second phalange |
1 |
Aves |
Charadriiformes |
Scopacidae |
upper beak cover/sheath |
1 |
Aves |
indeterminate |
Scopacidae |
coracoid |
1 |
Aves |
indeterminate |
Scopacidae |
cervical vertebra |
1 |
Chondrichthyes |
Lamniformes |
Carcharinidae |
vertebra indeterminate |
2 |
Chondrichthyes |
Selachii |
indeterminate |
vertebra indeterminate |
2 |
Chondrichthyes |
Rajifomes |
family indeterminate |
pharyngeal plate |
4 |
Osteichthys |
indeterminate |
family indeterminate |
spine indeterminate |
6 |
Osteichthys |
indeterminate |
family indeterminate |
scale indeterminate |
2 |
Osteichthys |
indeterminate |
family indeterminate |
vertebra indeterminate |
1 |
Osteichthys |
indeterminate |
family indeterminate |
fragment |
2 |
Osteichthys |
indeterminate |
med. fish indet. |
scale indeterminate |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
ctenoid scale |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
cycloid scale |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
atlas vertebra |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
thoracic vertebra |
2 |
Osteichthys |
indeterminate |
med. fish indet. |
precaudal vertebra |
5 |
Osteichthys |
indeterminate |
med. fish indet. |
caudal vertebra |
4 |
Osteichthys |
indeterminate |
med. fish indet. |
centrum vertebra |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
ultimate vertebra |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
vertebra indeterminate |
3 |
Osteichthys |
indeterminate |
med. fish indet. |
hyomandibular |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
dorsal spine |
1 |
Osteichthys |
indeterminate |
med. fish indet. |
haemal spine |
2 |
Osteichthys |
indeterminate |
med. fish indet. |
spine indeterminate |
4 |
Osteichthys |
indeterminate |
med. fish indet. |
fragment |
2 |
Osteichthys |
indeterminate |
Small fish indet. |
centrum vertebra |
1 |
Osteichthys |
indeterminate |
Small fish indet. |
spine indeterminate |
1 |
Osteichthys |
Perciformes |
Sciaenidae |
caudal vertebrae |
2 |
Osteichthys |
Perciformes |
Lutjanidae |
dorsal spine |
1 |
Osteichthys |
Siluriformes |
Ariidae |
prefrontal |
1 |
Osteichthys |
Siluriformes |
Ariidae |
parasphenoid |
1 |
Osteichthys |
Siluriformes |
Ariidae |
pectoral spine |
1 |
Osteichthys |
Siluriformes |
indeterminate |
pectoral spine |
1 |
Oral Pathology
Analysis of mandible and maxilla specimens revealed ancient evidence of moderate to severe abscesses and infections in the rat population (Armitage 1995a:19). In several specimens the teeth had fallen out partially or entirely due to the loosening of their roots from swelling of the alveoli (teeth sockets). Whether their actual loss took place antemortem or postmortem (postdeposition) can not be determined.
Rickets
Fig. 48. Black rat tibiae. Healthy, modern specimen (right), compared with specimen (00,401.2) from the Emanuel Point Ship (left) showing pathological changes suggestive of rickets. Both are immature specimens. Drawings by Kate Armitage.
During the examination of the rodent material, it was noticed that six limb bones, “all from very young (immature) rats, are noticeably stunted (i.e., abnormally shortened) and have a distinctive, abnormally “flaring”or ”cup-like” outgrowth of the end of the shaft; either proximally or distally, depending on the type of skeletal element involved (Armitage 1995a:20).” These pathological changes are typically associated with rickets, as discussed by Baker and Brothwell (1980:49).
Cannibalism
One black rat tibia exhibited numerous shallow grooves over its surface. According to Armitage (1995a:23), these depressions were made by rodent incisor teeth indicating that the specimen had been gnawed by another rat or rats. Similar markings were found also found on the non-rodent faunal material (see above).
House Mice
Two left tibiae of the house mouse were found intermixed among the other faunal material. Mus musculus L., or more properly, Mus domesticus, is the European house mouse (Armitage 1995b:1; Berry 1981:92).
Fig. 49. Unexpected, considering the large population of rats on board, two left mouse tibiae were found intermixed with other rodent remains.
Armitage considered “the finding of two or more mice” aboard the ship as “unexpected” considering the large black rat population (Armitage 1995b:1). According to Berry (1981: 93, 111 &113), “mice are certainly predated by rats . . . and “infestation [of buildings, and presumably ships] by rats keeps down mouse numbers to some extent, but situations where rats can live usually provide conditions for a large population of mice.”