An extinct north American porcupine with a South American tail.

New World porcupines (Erethizontinae) originated in South America and dispersed into North America as part of the Great American Biotic Interchange (GABI) 3-4 million years ago. Extant prehensile-tailed porcupines (Coendou) today live in tropical forests of Central and South America. In contrast, North American porcupines (Erethizon dorsatum) are thought to be ecologically adapted to higher-latitude temperate forests, with a larger body, shorter tail, and diet that includes bark.

Sabertooth carcass consumption behavior and the dynamics of Pleistocene large carnivoran guilds.

Apex predators play an important role in the top-down regulation of ecological communities. Their hunting and feeding behaviors influence, respectively, prey demography and the availability of resources to other consumers. Among the most iconic-and enigmatic-terrestrial predators of the late Cenozoic are the Machairodontinae, a diverse group of big cats whose hypertrophied upper canines have earned them the moniker "sabertooths.

Global long-term stability of individual dietary specialization in herbivorous mammals.

Dietary variation within species has important ecological and evolutionary implications. While theoreticians have debated the consequences of trait variance (including dietary specialization), empirical studies have yet to examine intraspecific dietary variability across the globe and through time. Here, we use new and published serial sampled δC values of herbivorous mammals from the Miocene to the present (318 individuals summarized, 4134 samples) to examine how dietary strategy (i.

Flexed-knee gait in children with cerebral palsy: a long-term follow-up study.

Aims: The purpose of this study was to evaluate the long-term outcome of adolescents with cerebral palsy who have undergone single-event multilevel surgery for a flexed-knee gait, followed into young adulthood using 3D motion analysis.

Patients And Methods: A total of 59 young adults with spastic cerebral palsy, with a mean age of 26 years (sd 3), were enrolled into the study in which their gait was compared with an evaluation that had taken place a mean of 12 years (sd 2) previously. At their visits during adolescence, the children walked with excessive flexion of the knee at initial contact and surgical or therapeutic interventions were not controlled between visits.

The effect of continuous intrathecal baclofen therapy on ambulatory children with cerebral palsy.

The effect of a continuous intrathecal infusion of baclofen (CITB) was retrospectively studied in 19 ambulatory children with cerebral palsy (aged 12.4±4.9 years at CITB initiation).