Paleomagnetic investigation of Plio-Pleistocene formations in Sangiran and Mojokerto, Java was carried out to date stratigraphic levels of Pithecanthropus fossils. Secular variation records of paleomagnetic field direction from the two areas show very consistent changes with some prominent features. The record for the past 3 million years obtained in Sangiran revises the magnetostratigraphy of earlier investigations and reveals stratigraphic levels of polarity boundaries and events. Based on correlation of the secular variation record of Mojokerto with that of Sangiran, magnetostratigraphy of Pleistocene formations in Mojokerto was established. The stratigraphic zone of Pithecanthropus in Sangiran ranges from the lower boundary of Jaramillo event to the Brunhes/Matuyama boundary, and the stratigraphic level of Homo modjokertensis lies at the lower border of Jaramillo event. Magnetochronologically it dates from about 0.73-0.97 m.y. for Sangiran and about 0.97 m.y. for Mojokerto.
Grooming behavior was studied from September 1990 to May 1992 in the provisioned troop of free-ranging Japanese macaques (Macaca fuscata) at Jigokudani Monkey Park, Japan. By confiscating what macaques picked up during grooming, we found that macaques pick up lice (Pedicinus obtusus and Pedicinuseurygaster) and the eggs of lice and eat them. Slow motion video replays were used to discriminate the prey of grooming. Most (98.9%) of what Japanese macaques picked up and ate during grooming were the eggs of lice. Hence, allogrooming has an altruistic function to eliminate the external parasites on others. In particular, grooming of infants by mothers appears to be important maternal care. On the other hand, in Japanese macaques, grooming is also insect-feeding behavior, and such selfish benefit may favor grooming under individual natural selection.
A fundamental biological process X(t|θ) is characterized by the evidence that the among-person variability of a systemic parameter θ is small. We came across this view during the study of the individual variability of drug-induced sufferings. This enables us the linearization of a fundamental biological process, assuming that one of unknown parameters is independent of time t. Then we can derive two practicable fundamental formulas, which hold not only for the growth of stature, but also for the dentition of deciduous tooth and for the metabolism of alcohol. The first formula implies the existence of a fixed point on the process. When X is derivable with respect to t, we can introduce the notion of the proper time τ, in place of the chronological time t. Then the individualized velocity dX/dτ is independent of the individuality. The idea is slightly generalized to obtain the almost-one parameter hypothesis, which is applied to the growth curve in the childhood and to the two-compartment model of the drug metabolism.