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Page history last edited by 525446@swansea.ac.uk 13 years, 4 months ago

A Spatial Analysis of Ring-tailed Lemurs at Monkey World

 

 

Species of Primate: Ring Tailed Lemur (Lemur catta) (See image)

 

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Primates

Family: Lemuridae

Genus: Lemur

Species: catta

 

Observation Period: 22/08/2010 1430hrs to 1530 hrs

Prevailing weather conditions: Overcast, dry

Observers: Caspian Johnson, Morgan Haylock, Rhys Evans 

 

Description of Individuals recorded:

 

Lemur 1

Caspian’s Lemur: Large male named Denton. Main identification characteristic is the loss of the left ear.

 

Lemur 2

Morgan’s Lemur: Small female. Main identification characteristic was the slight flattening of the left ear.

 

Lemur 3

Rhys’s Lemur: Medium sized male called white spot. Main identification characteristic was the large white spot on right cheek.

 

Biology, Behaviour and geographical distribution of ring tailed lemur

 

 

 

The Ring-tailed lemur is a prosimian primate native to the country of Madagascar. Within Madagascar they range furthur into the highlands than any other lemur and tend to inhabit gallery forests, deciduous forests and dry scrubland.

Adult Ring-tailed lemurs may reach up to 45cm in body length and weigh up to 3.5kg. They have a slender frame and narrow face with a fox like muzzle and as with all lemurs the hind limbs are longer than the forelimbs. Females have two sets of mammary glands however only one is functional.

The fur (pelage) is quite dense with the dorsal side ranging from grey to rosy brown and the ventral side coloured cream or white as this surface is mainly hidden while moving and can be used for sunbathing. The crown is dark grey with white or light grey ears, top of head and cheeks. The muzzle is almost black forming black rings around the eyes and the nose with a v shape along the top of the head. They share many adaptations with other lemurs such as the fingers, which are slender, padded and semi-dexterous.

The trademark black and white bushy tail of the lemur is usually longer than the body measuring up to 64cm in length and alternating black and white in 13 to 15 rings for each colour but always ending in a black tip. The tail is not prehensile and is used only for balance, communication and cohesion between groups.

Both males and females have furless scent glands in the form of apocrine and sebaceous glands in their genital regions, as well as antebrachial glands located on the inner surface of the forearm in the wrist region. However only the male has a horny spur which overlays the forearm scent gland and brachial glands on the auxiliary surface of their shoulders. Ring-tailed lemurs rely on these glands to produce scent that essential in intraspecific communication. Both females and males will scent mark horizontal and vertical surfaces with their anogenital glands. They do this by performing handstands and grasping the highest point with their feet to mark the location. The use of scent marking varies with sex and age. Males demarcate territories with their antebrachial and brachial glands to maintain intragroup dominance hierarchies.

A collision of two troops over resources is often resolved by aggressive displays being undertaken by the males. The males impregnate their tails with their scent and waft it at rival males, these are known as stink fights. The smelliest troop is the one with most numbers and thus the winners. This technique is similarly used during the mating season as a form of sexual overture.

Lemurs also mark territory using urine the difference being in territorial marking only a few drops of urine are produced compared to regular urination. It is used primarily by females to mark the edges of troop territory and is most commonly found on the borders where rival troops most frequent.

The Ring-tailed lemur favours the fruit and leaves of the tamarind tree known as the kily natively and will make up 50% of their diet when readily available.

Every morning due to the cold conditions of the night lemurs will sunbath. This is considered a group activity. On cold nights lemurs will huddle together to keep warm. This is known as a lemur ball. Although lemurs are quadrupedal they can rear up and stand on their hind legs balanced. This is usually used in aggressive displays and when threatened will jump and strike out with its nails and teeth in what is called jump fighting. However this type of behaviour is extremely rare outside of the breeding season. Other aggressive behaviours include the threat stare and the pulled back lip to intimidate. Unlike in most hierarchies the female will defend territorial disputes between different groups and defend the home range.

The ring tailed lemur is one of the most vocal primates and exhibits a wide variety of distinct vocalizations which range from alerting the group to a predators presence to maintain group cohesion during foraging and can be either simple or complex such as a purr or a sequence of clicks. Due to no predators at monkey world this could explain the lack of vocal communication. The most common vocalization is the moan and these sounds can variate from one to another.

The Ring-tailed lemur is a polygynous species however there is a slight hierarchy in which the dominant male will mate with more females than the rest and fighting as explained above is very common during the breeding season. Females will initiate breeding by presenting her backside and lifting her tail to a male. Once breeding has occurred gestation will last usually 135 days. One offspring is usually produced in September but twins are not uncommon. The baby lemur will weigh about 70g at birth and will be carried ventrally by the parent for the first 1 or 2 weeks and then dorsally. After two months the infants will begin to eat solid foods, are fully weaned at five months and reach sexual maturity between 2.5 and 3 years. Males do not partake much in rearing however the troop as a whole will be seen looking after the young regardless of age or sex.

Evolutionary history

Lemur fossil records from Madagascar all come from very recent times so little is known about the evolution of the ring tailed lemur. However lemurs seem to be more closely related than other prosimians, which is likely to be due to a single rafting event between 50-80 million years ago. Thus adaptive radiation and speciation has created the sheer diversity of lemurs shown today.

Aims

  

There are three of us working in this group to conduct a spatial analysis of Ring tailed lemurs in their enclosure at Monkey World (Map 1). We decided to record the behaviour and location of an individual lemur each then pool our data together at the end to create an average of the three. Therefore in essence, these three lemurs would represent the whole troop.  

 

The main aim this research is to determine the lemurs’ use of their enclosure during the observation period. We have also decided to record behaviour as to determine what behaviour is predominantly associated with which location.

 

Methods

 

Each of us chose one individual in the enclosure that we would study (one animal per person) and took a one hour spatial analysis of our chosen individual making a recording every minute on the minute.

Before the experiment we divided up into categories the main types of behaviour exhibited by the animals such as feeding, interaction and locomotion and non-locomotion.

We further divided these into sub categories to define that behaviour.

Each animal we studied could be seen at almost all times as the enclosure was open to the public so it was easy to follow our chosen individual around and monitor it effectively.

 

Behaviour table with picture key

 

 

A

Locomotion

Description

1

Walking

Under 2 body lengths/second

2

Running

Over 2 body lengths/second

3

Climbing

Moving in a tree or on a structure

4

Jumping

All limbs off the ground

B

Non-Locomotion

 

1

Sitting

In the upright position

2

Lying

horizontal

3

Sitting in elevated position (above 5 feet)

In the upright position in a tree or structure

4

Grooming self

Licking, scratching and rubbing

5

Standing

On all fours

6

Standing in an elevated position (above 5 feet)

On all fours in a tree or structure

C

Interaction

 

1

Grooming others

Licking, scratching, rubbing

2

Chased or chasing

following another lemur at a quick pace

3

Playing

interaction that subjectively derives enjoyment

4

Conflict

physical competition over a resource

5

Noise making

Audible noises generated internally by the lemurs

D

Feeding

 

1

Foraging on Ground

Looking for food terrestrially

2

Foraging arboreally

Looking for food arboreally

3

Drinking

Actively drinking water

 

Lemur Picture Key

To further clarify the definitions of the different behaviours we have included a picture key.

 

 

Sub-divisions

 

The enclosure has been split into 9 sub-divisions, as shown in the map of the enclosure. This will allow us to calculate time spent in each part of the enclosure and represent it as a percentage. Ultimately this will give us an idea of how the lemurs utilise their enclosure.

 

Enrichment and furnishing

 

Enrichments present in the enclosure included;

Lots of trees in the enclosure, mainly silver birch but few evergreens as well.

 

 

  • A man made sky path, that allowed the lemurs to move from one area of the enclosure to another above ground.
  • A wooden hut, giving shelter from the elements whenever needed.
  • Climbing ropes, hung off trees in the caged area for amusement.
  • Fresh nesting material provided every day for warmth and comfort.

  

Food was also spread around the enclosure, to be foraged for, as a form of activity.

 

Results

 

Raw Data:

 

 

Caspian

 

Rhys

 

Morgan

 

Time (mins)

Behaviour

Location

Behaviour

Location

Behaviour

Location

1

B3

2N

B1, C1

1C

B3

1C

2

B3

2N

B1, C1

1C

A3

1C

3

B3 D2

2N

B3

1C

D1

1C

4

B3

2N

B3

1C

A3

1C

5

B3

2N

B3

1C

B4

1C

6

A3

2N

B3

1C

A1

1C

7

A3

2N

B3

1C

B4

1C

8

B3

2N

B3

1C

B4 B3

1C

9

B3

2N

B3, C1

1C

A3

1C

10

B3 B4

2N

B3

1C

B3

1C

11

B3

2N

B3

1C

A3

1C

12

B3

2N

B3

1C

B3, C5

1C

13

A3

2C

B2

1C

B3

1C

14

C1 B3

2C

B3

1C

B4 B3

1C

15

C1 B3

2C

B2

1C

B4 B3

1C

16

C1 B3

2C

B2

1C

B3

1C

17

C1 B3

2C

B2

1C

B3

1C

18

B3

2C

B3

1C

B3

1C

19

B3

2C

B3

2C

C5, B3

1C

20

B3

2C

D1

2C

B3

1C

21

B3

2C

D1

2C

B3, C5

1C

22

B3

2C

D1

2C

B3

1C

23

C1 B3

2C

D1

2C

B3

2C

24

C1 B3

2C

D1

2C

A4

2C

25

D1

3C

D1

2C

A1

2C

26

B1

3C

D1

2C

D1

1C

27

B1

3C

D1

2C

A3

1C

28

B2

3C

C4, D1

2C

A3

1C

29

B3

3C

D1

2C

A1

1C

30

B5 C5

3C

D1

2C

A2

1C

31

B5 D1

3C

D1

2C

B3

1C

32

B1

3C

D1

2C

B3, C5

1C

33

A1

2C

A1

2C

D1

1C

34

B3

2C

B1

1C

D1

1C

35

A4

1N

B1

1N

A1

1C

36

A3

1N

B3

1N

B3

1C

37

A3

1N

B3

3N

B3

1C

38

B6

1N

A3

3N

B4 B3

1C

39

B6

1N

B3

3N

B3

1C

40

A3

1N

B3

3N

A2, C5

1C

41

A3

2N

A2

1N

A1

1C

42

A3

2N

A3

1C

B1

1C

43

A3

2N

A2

1C

B1, C5

1C

44

B3

2N

A1

1C

B1

1C

45

A3

2N

D1

2C

B1

1C

46

A3

3C

B1

2C

D1

1C

47

B5

3C

A1

2C

B2

1C

48

B1

3C

A1

2C

B3

1C

49

B1

3C

A1

2C

D2

1C

50

B5

3C

D2

1C

B4 B3

1C

51

B5

2C

D2

1C

B3

1C

52

A2

2C

D2

1C

B3

1C

53

A1

2C

D2

1C

C5, B3

1C

54

D1

2C

D2

1C

B3

1C

55

D1

2C

D2

1C

A4

1C

56

A1

2C

D2

1C

B3

1C

57

A1

2C

D2

1C

A2

1C

58

D1

2C

B2

1C

A3/4

1C

58

D1

2C

B2

1C

A2

1C

59

C1

2C

B2

1C

A1

1C

Table 1

 

 

Key  

Green cells

Elevated
Blue cell  FEEDING TIME HERE

 

Interpreted Data:

 

 

Graph 1. This pie chart shows that the individuals, on total, spent 57% of their time terrestrially and 47% in elevated situations. 

 

 

Graph 2. The bar graph above shows that, on average, the lemurs spent most of their time in the Central part of the enclosure, particularly in 1C. Little time was spent in the North and no time was spent in the South Part of the enclosure.

24 minutes into our observation period the lemurs it was feeding time for the lemurs. The feed was scattered by the keeper around locations 2C and 3C. The lemurs seemed to anticipate the arrival of the food by congregating in that area a few minutes before. 

 

 

This pie chart shows that in location 1C the individuals spent 56% of their time in an elevated situation (A3, B3 and D2). Individuals spent 66% of time conducting behaviours that involved no locomotion. This could be due to the house and pen being present in location 1C (Map 1). Therefore it seems the lemurs utilise this location as an area of rest. During our observation period, location 1C was the most preferred location with the lemurs spending 49.4% of their time here (Graph 2). 

 

 

This pie chart shows that in location 2C individuals spent 33% of their time foraging on the ground (D1). Only 29% of their time was spent in an elevated instance (A3 and B3). More time than in any other location was allocated to direct interaction with one another at 15% (C1 and C4). This part of the enclosure is an open area with a low tree density perhaps accounting for it being utilised as a sociable area for the lemurs. This location was the second most preferred by the lemurs with them spending 26.6% of their time there (Graph 2).

 

 

This pie chart shows that in location 3C individuals spent 60% of their time standing on all fours and sitting upright (B5 and B1 respectively). This area, as you can see from map 1 has very little in the way of vegetation or structures. It is a clear space that is utilised as the feeding zone. This location was the 4th most preferred by the lemurs with them spending 7.2% of their time there (Graph 2).

 

 

This pie chart shows that in location 1N individuals spent 60% of their time in the trees (B6, A3 and B3). 30% of their time in this area is spent running and jumping, between trees, indicating its an area for exercise and fast paced play (A2 and A4). This is likely due to this area being densely populated with trees. This location was the 5th most preferred location with the lemurs spending only 5% of their time there (Graph 2).

 

 

This pie chart shows that in location 2N individuals spent 95% of their time climbing or resting in trees (B3, D2 and A3). Again this area is densely populated with trees (see map 1). This location in particular offers escape from human visitors, as it is isolated. This location was the 3rd most preferred location of the lemurs with them spending 9.4% of their time here (Graph 2).

 

 

This pie chart shows that in location 3N individuals spent 100% of their time in an elevated position. However as you can see from Graph 2, the lemurs only spent 2.2% of their time in this location. Due to the forested nature of this area though, all time spent here was spent in arboreal positions. Bar the Southern locations, 3N was the location the lemurs spent the least amount of their time with only 2.2%.

Conclusion

From the analysis of the data there is evidence that suggests some behaviours are more favoured in certain areas of the enclosure. This is likely to be due to the difference in physical characteristics of each location.

The lemurs seemed to prefer utilizing the Central zone of the enclosure. However, the results were taken as totals of the behaviour and locations of all 3 lemurs and Morgan’s lemur spent 95% of its time in location 1C (Table 1). As the location of this single lemur remained monotonous the results, as averages, did not reflect accurately how the lemurs utilised their enclosure as a group. As you can see from Map 1, the central areas contain the house, the pen and the open area in which the animals are fed. Also during our observation period, at minute 24 (Table 1) food was dispersed in this area. This effectively compromised our observation due to it attracting all the lemurs to this location, therefore it was not an accurate representation of how their enclosure is normally utilised.

Less time was spent in the North zone of the enclosure, however the majority of time spent here by lemurs was elevated (Map 2), this could be due to the large amount of trees and foliage, giving them a selection of climbing apparatus.

As you can see from Graph 1, 57% of their time was spent on the ground. In the wild, lemurs only spend on average 33% of their time on the ground. This 25% difference in the utilisation of their 3 dimensional environment is likely to have risen from the lack of predators at Monkey World. Despite this difference, the lemurs did still heavily utilise the array of elevated structures and trees in their enclosure.

Finally the South zone of the enclosure had zero time spent here, this could be due to the human path that dominated its area, perhaps they didn’t want to get to close to human contact. There was also a lack of things to climb as the vegetation consisted mainly of sparsely spread shrubs. 

 

 

 

 

 

 

 

 

 

 

 

Comments (1)

Paul Brain said

at 2:08 pm on Nov 15, 2010

Some people seem to be having a problem with Common chimpanzee page 2. Is everyone else OK?

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