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Holding-on: co-evolution between infant carrying and grasping behaviour in strepsirrhines

View Article: PubMed Central - PubMed

ABSTRACT

The origin and evolution of manual grasping remain poorly understood. The ability to cling requires important grasping abilities and is essential to survive in species where the young are carried in the fur. A previous study has suggested that this behaviour could be a pre-adaptation for the evolution of fine manipulative skills. In this study we tested the co-evolution between infant carrying in the fur and manual grasping abilities in the context of food manipulation. As strepsirrhines vary in the way infants are carried (mouth vs. fur), they are an excellent model to test this hypothesis. Data on food manipulation behaviour were collected for 21 species of strepsirrhines. Our results show that fur-carrying species exhibited significantly more frequent manual grasping of food items. This study clearly illustrates the potential novel insights that a behaviour (infant carrying) that has previously been largely ignored in the discussion of the evolution of primate manipulation can bring.

No MeSH data available.


Related in: MedlinePlus

Mean proportion of the different grip types used to grasp big and hard items in relation to infant carrying (fur: N = 15, Nind = 53, Ngrip = 1432; mouth: N = 6, Nind = 24, Ngrip = 497; Mann-Whitney U tests; **P < 0.01).Data are represented as mean ± SEM.
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f2: Mean proportion of the different grip types used to grasp big and hard items in relation to infant carrying (fur: N = 15, Nind = 53, Ngrip = 1432; mouth: N = 6, Nind = 24, Ngrip = 497; Mann-Whitney U tests; **P < 0.01).Data are represented as mean ± SEM.

Mentions: As it is know that food size and mobility impact grasping24 we here analysed only grasping of large and hard static food items. A MANOVA performed on the transformed proportion of the different grip types while grasping big and hard items (Table S1) indicated a significant effect of infant carrying (Wilks’ λ = 0.47, F1, 15 = 3.43, P = 0.029). In order to grasp big and hard food items, fur-clinging species were observed to use significantly less mouth grips during feeding (36 ± 6%, N = 16, Nind = 53, Ngrip = 1432) than oral-carrying species (71 ± 7%, N = 6, Nind = 24, Ngrip = 497) (Mann-Whitney U test: W = 10, P = 0.005; Fig. 2). Moreover, fur-clinging species were observed to use significantly more unimanual grips during feeding (52 ± 7%, N = 15, Nind = 53, Ngrip = 1432) than oral-carrying species (11 ± 5%, N = 6, Nind = 24, Ngrip = 497) (Mann-Whitney U test: W = 83.5, P = 0.003; Fig. 2). No significant differences were observed between the two groups regarding the proportion of combined oral and unimanual grips (Mann-Whitney U test: W = 41, P = 0.78; Fig. 2), oral and bimanual grips (Mann-Whitney U test: W = 29.5, P = 0.143; Fig. 2), or bimanual grips (Mann-Whitney U test: W = 59.5, P = 0.23; Fig. 2). Bimanual grips are rarely used by lemurs (Fig. 2) and will not be discussed further.


Holding-on: co-evolution between infant carrying and grasping behaviour in strepsirrhines
Mean proportion of the different grip types used to grasp big and hard items in relation to infant carrying (fur: N = 15, Nind = 53, Ngrip = 1432; mouth: N = 6, Nind = 24, Ngrip = 497; Mann-Whitney U tests; **P < 0.01).Data are represented as mean ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121892&req=5

f2: Mean proportion of the different grip types used to grasp big and hard items in relation to infant carrying (fur: N = 15, Nind = 53, Ngrip = 1432; mouth: N = 6, Nind = 24, Ngrip = 497; Mann-Whitney U tests; **P < 0.01).Data are represented as mean ± SEM.
Mentions: As it is know that food size and mobility impact grasping24 we here analysed only grasping of large and hard static food items. A MANOVA performed on the transformed proportion of the different grip types while grasping big and hard items (Table S1) indicated a significant effect of infant carrying (Wilks’ λ = 0.47, F1, 15 = 3.43, P = 0.029). In order to grasp big and hard food items, fur-clinging species were observed to use significantly less mouth grips during feeding (36 ± 6%, N = 16, Nind = 53, Ngrip = 1432) than oral-carrying species (71 ± 7%, N = 6, Nind = 24, Ngrip = 497) (Mann-Whitney U test: W = 10, P = 0.005; Fig. 2). Moreover, fur-clinging species were observed to use significantly more unimanual grips during feeding (52 ± 7%, N = 15, Nind = 53, Ngrip = 1432) than oral-carrying species (11 ± 5%, N = 6, Nind = 24, Ngrip = 497) (Mann-Whitney U test: W = 83.5, P = 0.003; Fig. 2). No significant differences were observed between the two groups regarding the proportion of combined oral and unimanual grips (Mann-Whitney U test: W = 41, P = 0.78; Fig. 2), oral and bimanual grips (Mann-Whitney U test: W = 29.5, P = 0.143; Fig. 2), or bimanual grips (Mann-Whitney U test: W = 59.5, P = 0.23; Fig. 2). Bimanual grips are rarely used by lemurs (Fig. 2) and will not be discussed further.

View Article: PubMed Central - PubMed

ABSTRACT

The origin and evolution of manual grasping remain poorly understood. The ability to cling requires important grasping abilities and is essential to survive in species where the young are carried in the fur. A previous study has suggested that this behaviour could be a pre-adaptation for the evolution of fine manipulative skills. In this study we tested the co-evolution between infant carrying in the fur and manual grasping abilities in the context of food manipulation. As strepsirrhines vary in the way infants are carried (mouth vs. fur), they are an excellent model to test this hypothesis. Data on food manipulation behaviour were collected for 21 species of strepsirrhines. Our results show that fur-carrying species exhibited significantly more frequent manual grasping of food items. This study clearly illustrates the potential novel insights that a behaviour (infant carrying) that has previously been largely ignored in the discussion of the evolution of primate manipulation can bring.

No MeSH data available.


Related in: MedlinePlus