Infanticide by Males and its Implications

Cover......Page 1
Half-title......Page 3
Title......Page 5
Copyright......Page 6
Contents......Page 7
Contributors......Page 10
Foreword......Page 13
Infanticide by males: prospectus......Page 17
Acknowledgments......Page 22
Part I Introduction......Page 23
Cute and brute......Page 25
Nature revisited......Page 28
Non-adaptationist explanations: critique from within the paradigm......Page 29
Science is politics: critique from outside the paradigm......Page 35
Accusation: science is sexist......Page 37
Accusation: science is capitalistic......Page 38
Accusation: science is oppressive......Page 39
Amongst the fallibles......Page 40
Introduction......Page 43
Behavioral contexts......Page 47
Killers’ relatedness to infants......Page 52
Weaning status of infants......Page 53
Speeding up return to ovarian cycling......Page 55
Subsequent sexual access to mother......Page 56
Injuries......Page 57
Conclusion......Page 58
Social pathology......Page 59
Infanticide as a by-product of male aggression......Page 61
Exploitation: cannibalism......Page 62
Resource competition......Page 63
Elimination of future rivals......Page 64
Conclusion......Page 66
Defense by females......Page 67
Defense by males......Page 69
Paternity......Page 70
Why infanticide between groups?......Page 72
The genetics of infanticide by males......Page 73
Should females resist?......Page 75
Acknowledgments......Page 76
Introduction......Page 77
Lactation/gestation ratios......Page 79
Taxonomic distribution of infanticide records......Page 80
L/G and infanticide......Page 83
Discussion......Page 85
Part II Infanticide by males: case studies......Page 89
Introduction......Page 91
Study site and monitoring techniques......Page 94
Measures......Page 99
The relation of number of males to incursion and infanticide......Page 101
Consequences of infanticide for fecundity of females......Page 103
Discussion......Page 105
Acknowledgments......Page 113
Introduction......Page 115
Ramnagar: habitat, population, and methods......Page 117
Events......Page 118
Participants and paternities......Page 119
Infanticide in a multimale population......Page 121
Definitions......Page 126
Influencing components......Page 127
Assumptions......Page 128
Male immigration and infanticide......Page 131
The number of unweaned infants and infanticide......Page 133
Life history variables, population characteristics and infanticide......Page 136
Acknowledgments......Page 137
Introduction......Page 139
Infant wounding in Moremi chacma baboons......Page 142
Case 2......Page 143
Case 3......Page 146
Case 6......Page 147
Case 7......Page 148
Case 10......Page 149
Summary......Page 150
Female AL and her infant AA......Page 151
Female SY and her infant SU......Page 154
Infant mortality......Page 155
Variability in male infanticidal behavior......Page 156
Infanticide as a facultative strategy......Page 160
Friendships and male defense of infants......Page 162
Conclusions......Page 165
Acknowledgments......Page 166
Introduction......Page 169
Study area and subjects......Page 170
Changes in social organization......Page 171
Infanticide in Thomas’s langurs......Page 172
Infanticide and female transfer......Page 174
Tenure-related changes......Page 175
Males......Page 179
Females......Page 181
Females......Page 183
Male decisions......Page 185
Female decisions......Page 188
Comparisons with other taxa......Page 190
Acknowledgments......Page 192
A thumbnail sketch of infanticide in rodents......Page 194
The evolution of infanticide in rodents......Page 196
Some important caveats......Page 197
Defining infanticidal traits......Page 198
Comparative analyses......Page 202
The evolution of infanticide......Page 203
How many times did infanticide evolve in rodents?......Page 204
Did Bruce effects evolve as a counterstrategy to infanticide by males?......Page 206
How does infanticide influence rodent social organization?......Page 209
Does the risk of infanticide by females lead to female territoriality?......Page 210
The evolution of infanticide in rodents......Page 211
Conservation implications of rodent infanticide......Page 212
Acknowledgments......Page 213
Introduction......Page 214
Infanticide by males: kind of evidence and frequency of occurrence......Page 216
Patterns of infanticide by males: contrasts within and between species......Page 220
Takeover and infanticide: independent targets of selection......Page 225
Factors favoring the evolution of infanticide versus alternative behaviors......Page 227
Prospective infanticide as a paternity insurance strategy......Page 231
Counterstrategies of females......Page 233
Conclusions......Page 234
Part III Behavioral consequences of infanticide by males......Page 237
Protectors......Page 239
Avoiding detection by concealment......Page 243
Avoiding attack by deception......Page 244
Neonatal transport......Page 249
Sedentary feeding......Page 252
Travel economy......Page 253
Acknowledgments......Page 254
Introduction......Page 255
Male defense and male–female social relationships......Page 256
Alternative potential benefits to females......Page 257
Alternative potential benefits to males......Page 259
Insects......Page 261
Birds......Page 264
Rodents......Page 266
Mountain gorillas......Page 268
Chacma baboons......Page 269
Gibbons......Page 270
The female perspective......Page 279
The male perspective......Page 281
The importance of studying costs......Page 282
Acknowledgments......Page 284
Introduction......Page 285
Hanuman langurs......Page 287
Savanna baboons......Page 288
Mangabeys......Page 290
Macaques......Page 291
Conclusion......Page 292
Observations......Page 293
Interpretation: the agonistic buffering hypothesis......Page 295
Infants as mediators of cooperative male–male relationships......Page 298
Interspecific patterns......Page 301
Discussion......Page 302
Acknowledgments......Page 308
Costs and benefits of dispersal......Page 309
Female dispersal and infanticide risk......Page 310
Data extracted from the literature......Page 313
General patterns in female dispersal......Page 314
Male infanticide and female dispersal......Page 315
“Remaining with the father” hypothesis......Page 325
“Reducing the probability of takeover” hypothesis......Page 328
Discussion......Page 330
Proximate mechanisms......Page 331
Proximate mechanisms......Page 333
Ultimate cause......Page 334
Ultimate cause......Page 335
Main conclusion......Page 336
Acknowledgments......Page 337
Introduction......Page 338
Predictions to be tested......Page 340
Direct benefits......Page 343
Delayed benefits......Page 344
Assessing vulnerability......Page 347
Validation of vulnerability criteria......Page 360
Polyandrous mating......Page 362
Means of achieving polyandry......Page 366
Postconception mating......Page 367
Abandonment of unborn offspring......Page 369
Interactions among the various tactics......Page 370
Discussion......Page 371
Alternative pressures on mammalian reproductive behavior......Page 372
Effects of social and biological constraints......Page 373
Additional countertactics?......Page 374
Conclusion......Page 375
Acknowledgments......Page 376
Introduction......Page 377
The female dilemma......Page 378
The concept of concealed ovulation......Page 380
Unpredictable ovulation and follicular phase variance......Page 383
Testing the consequences: paternity distribution......Page 388
Duration of the follicular phase......Page 389
Taxonomic contrast in female control......Page 391
Substrate use......Page 393
Canine dimorphism......Page 394
Female control and follicular phase length in catarrhines......Page 396
Demographic context and the potential for polyandrous matings......Page 397
Number of mating partners......Page 398
Number of males in group......Page 399
Discussion......Page 400
Implications for humans......Page 402
Acknowledgments......Page 403
Introduction......Page 404
Ecological and intersexual pressures in primate social evolution......Page 405
Predictions and methods......Page 409
Predation......Page 410
Female intrasexual competition......Page 411
Infanticide risk......Page 412
Statistics and phylogenetic comparative methods......Page 413
Predation......Page 414
Female intrasexual competition......Page 416
Infanticide......Page 417
Harassment......Page 422
Discussion......Page 424
Weaknesses of the interspecific approach to study infanticide and harassment......Page 426
Acknowledgments......Page 428
Part IV Infanticide by females......Page 437
Introduction......Page 439
Definitions and hypotheses......Page 440
Resource competition......Page 441
Exploitation......Page 443
Implications of infanticide by females for the evolution of mammalian social systems......Page 445
Background and vulnerability......Page 447
Potential benefits to the perpetrator......Page 448
Counterstrategies and implications......Page 449
Background and vulnerability......Page 450
Counterstrategies and implications......Page 451
Background and vulnerability......Page 452
Potential benefits to the perpetrator and counterstrategies......Page 453
Within-group infanticide......Page 454
Direct cases: potential benefits to the perpetrator......Page 455
Indirect cases: potential benefits to the perpetrator......Page 456
Background and vulnerability......Page 457
Potential benefits to the perpetrator......Page 459
Conclusions......Page 460
Acknowledgments......Page 462
Introduction......Page 463
Unmarried mothers and their offspring in Ditfurt (Sachsen-Anhalt, Germany, 1655–1939)......Page 467
Does it pay to abandon the bastard? – evidence from the Krummhörn......Page 473
Upgrading one’s mate value: abandoning children to get a man......Page 476
Conclusions......Page 480
Acknowledgments......Page 481
Part V Conclusion......Page 483
Introduction......Page 485
Why cannot female mammals avoid infanticide risk altogether?......Page 487
Ecological and social correlates of observed rates of infanticide......Page 489
Male replacement rate......Page 491
Sexual dimorphism......Page 495
One-versus multimale groups......Page 498
Diet......Page 502
Female responses to male infanticidal threat and their ecological implications......Page 503
Conclusions: on the causes of variation in rates of infanticide......Page 506
Why was infanticide ignored for so long as a significant selection pressure on social systems?......Page 507
Infanticide rates and population disturbance......Page 509
Acknowledgments......Page 510
References......Page 511
Species index......Page 571
Subject index......Page 581