Student assignment. (requirement for course by Peter Kabai)

Group Territoriality of African Lions

By Eva Mari Aastorp

The African Lions, Panthera leo, is a species that forms fission-fussion social groups called prides. These prides can range from 2-18 related adults. To maximize their chances for reproduction, the male lions form life long alliances with other males. Most of the male companions are brother and cousins that grew up together, however they may also consist of non relatives that teamed up after solitary nomadic phase. One single pride can range of 1-9 male lions. Together they try to protect the pride from other rivals. The rest of the pride consist of lionesses and they also have a variety of group level activities. In a pride the female lions shares the nursing and defending of cubs and hunting.

The lions are territorial animals. The territory is essential for successful breeding and can only be held by two or more females. Territory size depends on features such as prey availability, permanent water sources and suitable hinding places for young cubs. There are no dominance hierarchy among the lionesses. All the group members have equal access of the territory benefits. Both male and female claim their ownership by roaring. The lionesses uses the number of roars of their opponents and compares it with the number of their own pride present. The female territorial behaviour is therfore influenced by odds and are more likely to respond if they outnumber the intruders. The male behaviour in such situations differs a lot from the female. They tend to approach enemies regardless the odds.

The group territoriality does not only differ within a group, but also between different prides as well. Several studies by researchers can confirm this. Such studies have been done by the researcher Robert Heinohn. One of his many studies of lions was focused on group territoriality of different prides living close to each other in Tanzania;

The Ngorongoro crater is a volcanic caldera that consits of 7 prides living of a density approximately one lion per 2,5km². The area has large non-migrating preys and lions produces a large number of cubs each year. Their body size is bigger than the lions outside of the crater.

Serengeti has 17 prides living of a density approximately one lion per 10 km². The area has seasonal migration of large herbivores during the rainy season. The remaining months the area has little preys to offer.

During the research the prides had approximately 2-17 juveniles each.

To observe the differences, playbacks of lion roars was used to simulate intruders.

There were 16 cases when the pride failed to approach in the Serengeti, whereas all prides always responded in the crater

One pride, K2, in the Serengeti actively retreated each time. The group consisted of 2 females and 3 juveniles. Their behaviour was completely different than of the other prides. Their complete incompatibility of the behaviour is due to that the pride was a offshoot of a larger pride and had no well defined territory. This pride was therefore excluded from the research.

There were a similar offshoot in the Serengeti area, Simba west, (2 females and 3 subadults), but their behaviour differed a lot from the K2 pride in the presence of intruders. They always approached intruders even when their adults where outnumbered three to two.

A small pride in the crater, Lakettes, (3 adults and 3 juveniles), always responded and confronted their opponents. This group showed one of the quickest responses to the playbacks.

The speed of approach also differed from the Serengeti lions and the Ngorongoro lions. When the odds of winning were lower, the Serengetti lionesses approached more slowely and cautiously whereas the lionesses in the crater tended to respond either at the same pace or even more quickly at low odds.

The research also showed different behaviour between the individuals in a single pride. Some lions always led the approach, while others always lagged behind. These strategies can be divided in 4 groups;

1) Unconditional cooperators; who always lead the respons

2) Unconditional cooperators; who always lag behind

3) Conditional cooperators; who lag least when they are most needed

4) Conditional laggards; who lag farthest behind when they are most needed.

A female lion from group 1 was more cautiously and looked more often behind at her companions during an approach when paired with a laggard.

Female juveniles are more sensitive than the adults to the odds of winning and are more likely to join the adults in defence as they mature. But the presence of the juveniles in this research had no significantly affect.

The prides in the Serengeti and the crater showed perceptible differences in group territoriality. The causes may be many but one strikingly reason is their differences in the ecological circumstances.

The prides in the Serengeti ecosystem has only seasonal food supply and lives in more feast and famine conditions. This causes the lions to wander over a great range of area and so poorly defined territories are established. These territories becomes then less valuable for the lions and will therefor not always take the risk of severe injuries from a territorial fight. The low density of lions also contributes to less conflicts between the different prides living close to each other in the Serengeti.

The prides in the Ngorongoro crater lives in Africas highest density of lions, due to the great availibilty of non-migrating prey species. This increases the conflicts and mortality among the prides and promote a more aggressive behaviour in the lions. Because of the great supplies of preys inside the volcanic caldera rather than outside, the territories are much more valuable for the lions in the crater. To be pushed out of the crater by opponents leads to much poorer conditions and may be severe to a pride. This may contribute the lions to take higher risks defending their territory. The resident lions are usually physically stronger than the intruders. This is due to the more stable feeding condition than for a lion without a territory. The Ngorongoro lions were not only stronger, but had also much larger body size than of their co-species outside the crater. This makes it very difficult for outsiders to invade the area. No immigration of other lions have been observed for at least 30 years. These territorial conflicts are then fights that the lions are accustomed to win and may also contribute to the more aggressive behaviour towards foreign opponents regardless the odds.

Also the individuals in the cooperative group showed different strategies when the pride confronted a treat. Some females cooperate unconditionally and others only cooperate when most needed. These responses amphasizes the great diversity of individual behaviour within a pride as well. It shows us that individuals in a pride has the cognitive ability for their self-interest. They are not only protecting the group`s interests but also their own interests. The lionesses clearly recognized the laggards in the pride, however they never punished the laggards thus the different individual behaviour continued.

Finding territories cost time and energy. When a territory is established the pride gain several benefits such as; secure caloric requirements more quickly, increased access to mates and better and more secure way of rearing the youngs. There are both high quality and low quality territories. When it comes to defending the territory the behaviour is rather complex and are influenced by a great diversity of factors such as body size, odds, ecological circumstances etc. The degree of relatedness do not affect the decision to approach invaders. The territorial behaviour differs between the individuals in a group as well as between different prides. The decision of defending a territory can be explained by the cost/benefit principle. The lions take the risk of injuries when the territory is economically defendable, but when the odds are low and the cost exceeds the benefits, the lions usually retreat and tries to establish a new territory elsewhere.

References:

Research articles;

1)Group territoriality of two populations of African Lions by Robert Heinsohn

2) Complex cooperative strategies in group territorial African lion by Robert Heinsohn and Graig Parker

3) Ecological change, group territoriality, and population dynamics in Serengeti lions by Graig Parker, Ray Hilborn, Anna Mosser, Bernhard Kissui, Markus Borner, Grant Hopcraft, John Wilmshurst, Simon Mduma and Anthony R. E. Sinclair

4) Modes of cooperation durring territorial defense by African lions by Jon Grinnell

5) Divided we fall; cooperation among lions by Graig Parker and Anne E. Pusey

6) Effects on kinship on territorial conflicts among groups of lions, Panthera leo by Goran Spong and Scott Creel.

Books;

7) Animal behavior on evolutionary approach by Alcock

8) Prespectives on animal behavior by Goodenough, McGuire and Wallace

9) Essential animal behavior by Scott

Links;

10) www.lionresearch.org

11) www.nature.com

12) www.ornithology.com

13) www.african-lions.org

14) www.catsg.org

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Group Territoriality of African Lions By Eva Mari Aastorp The African Lions, Panthera leo, is a species that forms fission-fussion social groups called prides. These prides can range from 2-18 related adults. To maximize their chances for reproduction, the male lions form life long alliances with other males. Most of the male companions are brother and cousins that grew up together, however they may also consist of non relatives that teamed up after solitary nomadic phase. One single pride can range of 1-9 male lions. Together they try to protect the pride from other rivals. The rest of the pride consist of lionesses and they also have a variety of group level activities. In a pride the female lions shares the nursing and defending of cubs and hunting. The lions are territorial animals. The territory is essential for successful breeding and can only be held by two or more females. Territory size depends on features such as prey availability, permanent water sources and suitable hinding places for young cubs. There are no dominance hierarchy among the lionesses. All the group members have equal access of the territory benefits. Both male and female claim their ownership by roaring. The lionesses uses the number of roars of their opponents and compares it with the number of their own pride present. The female territorial behaviour is therfore influenced by odds and are more likely to respond if they outnumber the intruders. The male behaviour in such situations differs a lot from the female. They tend to approach enemies regardless the odds. The group territoriality does not only differ within a group, but also between different prides as well. Several studies by researchers can confirm this. Such studies have been done by the researcher Robert Heinohn. One of his many studies of lions was focused on group territoriality of different prides living close to each other in Tanzania; The Ngorongoro crater is a volcanic caldera that consits of 7 prides living of a density approximately one lion per 2,5km². The area has large non-migrating preys and lions produces a large number of cubs each year. Their body size is bigger than the lions outside of the crater. Serengeti has 17 prides living of a density approximately one lion per 10 km². The area has seasonal migration of large herbivores during the rainy season. The remaining months the area has little preys to offer. During the research the prides had approximately 2-17 juveniles each. To observe the differences, playbacks of lion roars was used to simulate intruders. There were 16 cases when the pride failed to approach in the Serengeti, whereas all prides always responded in the crater One pride, K2, in the Serengeti actively retreated each time. The group consisted of 2 females and 3 juveniles. Their behaviour was completely different than of the other prides. Their complete incompatibility of the behaviour is due to that the pride was a offshoot of a larger pride and had no well defined territory. This pride was therefore excluded from the research. There were a similar offshoot in the Serengeti area, Simba west, (2 females and 3 subadults), but their behaviour differed a lot from the K2 pride in the presence of intruders. They always approached intruders even when their adults where outnumbered three to two. A small pride in the crater, Lakettes, (3 adults and 3 juveniles), always responded and confronted their opponents. This group showed one of the quickest responses to the playbacks. The speed of approach also differed from the Serengeti lions and the Ngorongoro lions. When the odds of winning were lower, the Serengetti lionesses approached more slowely and cautiously whereas the lionesses in the crater tended to respond either at the same pace or even more quickly at low odds. The research also showed different behaviour between the individuals in a single pride. Some lions always led the approach, while others always lagged behind. These strategies can be divided in 4 groups; 1) Unconditional cooperators; who always lead the respons 2) Unconditional cooperators; who always lag behind 3) Conditional cooperators; who lag least when they are most needed 4) Conditional laggards; who lag farthest behind when they are most needed. A female lion from group 1 was more cautiously and looked more often behind at her companions during an approach when paired with a laggard. Female juveniles are more sensitive than the adults to the odds of winning and are more likely to join the adults in defence as they mature. But the presence of the juveniles in this research had no significantly affect. The prides in the Serengeti and the crater showed perceptible differences in group territoriality. The causes may be many but one strikingly reason is their differences in the ecological circumstances. The prides in the Serengeti ecosystem has only seasonal food supply and lives in more feast and famine conditions. This causes the lions to wander over a great range of area and so poorly defined territories are established. These territories becomes then less valuable for the lions and will therefor not always take the risk of severe injuries from a territorial fight. The low density of lions also contributes to less conflicts between the different prides living close to each other in the Serengeti. The prides in the Ngorongoro crater lives in Africas highest density of lions, due to the great availibilty of non-migrating prey species. This increases the conflicts and mortality among the prides and promote a more aggressive behaviour in the lions. Because of the great supplies of preys inside the volcanic caldera rather than outside, the territories are much more valuable for the lions in the crater. To be pushed out of the crater by opponents leads to much poorer conditions and may be severe to a pride. This may contribute the lions to take higher risks defending their territory. The resident lions are usually physically stronger than the intruders. This is due to the more stable feeding condition than for a lion without a territory. The Ngorongoro lions were not only stronger, but had also much larger body size than of their co-species outside the crater. This makes it very difficult for outsiders to invade the area. No immigration of other lions have been observed for at least 30 years. These territorial conflicts are then fights that the lions are accustomed to win and may also contribute to the more aggressive behaviour towards foreign opponents regardless the odds. Also the individuals in the cooperative group showed different strategies when the pride confronted a treat. Some females cooperate unconditionally and others only cooperate when most needed. These responses amphasizes the great diversity of individual behaviour within a pride as well. It shows us that individuals in a pride has the cognitive ability for their self-interest. They are not only protecting the group`s interests but also their own interests. The lionesses clearly recognized the laggards in the pride, however they never punished the laggards thus the different individual behaviour continued. Finding territories cost time and energy. When a territory is established the pride gain several benefits such as; secure caloric requirements more quickly, increased access to mates and better and more secure way of rearing the youngs. There are both high quality and low quality territories. When it comes to defending the territory the behaviour is rather complex and are influenced by a great diversity of factors such as body size, odds, ecological circumstances etc. The degree of relatedness do not affect the decision to approach invaders. The territorial behaviour differs between the individuals in a group as well as between different prides. The decision of defending a territory can be explained by the cost/benefit principle. The lions take the risk of injuries when the territory is economically defendable, but when the odds are low and the cost exceeds the benefits, the lions usually retreat and tries to establish a new territory elsewhere. References: Research articles; 1)Group territoriality of two populations of African Lions by Robert Heinsohn 2) Complex cooperative strategies in group territorial African lion by Robert Heinsohn and Graig Parker 3) Ecological change, group territoriality, and population dynamics in Serengeti lions by Graig Parker, Ray Hilborn, Anna Mosser, Bernhard Kissui, Markus Borner, Grant Hopcraft, John Wilmshurst, Simon Mduma and Anthony R. E. Sinclair 4) Modes of cooperation durring territorial defense by African lions by Jon Grinnell 5) Divided we fall; cooperation among lions by Graig Parker and Anne E. Pusey 6) Effects on kinship on territorial conflicts among groups of lions, Panthera leo by Goran Spong and Scott Creel. Books; 7) Animal behavior on evolutionary approach by Alcock 8) Prespectives on animal behavior by Goodenough, McGuire and Wallace 9) Essential animal behavior by Scott Links; 10) www.lionresearch.org 11) www.nature.com 12) www.ornithology.com 13) www.african-lions.org 14) www.catsg.org

Notes (if any) by Peter Kabai:
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