Row Length Research Articles

Climatic change and body size in two species of Japanese rodents

Using museum specimens, we studied temporal changes in skull size in two species of Japanese rodents, the large Japanese field mouse (Apodemus speciosus) and Pratt's vole (Eothenomys smithii = E. kageus) during the 20th century. We used the greatest length of the skull (GTL), zygomatic breadth (ZB), narrowest width of the skull across the interorbital region (IC) and the length of the upper cheek teeth row (M) as indicators to such changes. We found that GTL and ZB (but not IC and M) increased during the study period in mice, and that IC and M (but not GTL and ZB) increased marginally in voles. We attribute these changes to elevated ambient minimal temperatures, which increased food availability and energy savings for the mice, and required diet change in the voles. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 82, 263–267.

MORPHOLOGICAL DIFFERENTIATION BETWEEN ADJACENT POPULATIONS OF ASIATIC BLACK BEARS, URSUS THIBETANUS JAPONICUS, IN NORTHERN JAPAN

The skull morphology of black bears inhabiting 2 distributional ranges isolated by 2 river basins in northern Japan was compared in order to examine whether the animals represent different populations. We found substantial differences in relative width of the skull and measurements related to the masticatory apparatus, especially in the length of the molar row and palatal width; the former already differs at 1 year of age when the eruption of permanent teeth occurs, suggesting a genetic basis for the difference. Jackknifed classification was able to correctly assign all adult specimens except 1. The results indicate that bears from these 2 areas belong to different populations that might have been isolated for a considerable period, and gene flow between them is limited, even though the distance between the 2 ranges is only several kilometers at the narrowest point. The Japanese black bear might live in small, isolated local populations.

Chromosomal aberrancy and the level of fluctuating asymmetry in black-striped mouse (Apodemus agrarius): effects of disturbed environment.

Analysis of chromosomal aberrations in bone marrow cells and determination of the level of fluctuating asymmetry (FA) for eight bilateral cranial traits were used to estimate effects of disturbed environment on natural populations of small mammals. During the spring and fall of 1994-2000 (except in 1999) black-striped mice (Apodemus agrarius) were collected from a polluted industrial area (Pancevo) and from an unpolluted reference site (Cer) in Serbia and Montenegro. Mice from the polluted area had significantly higher mean number of aberrant cells per individual than those in the reference site (p<0.01). Both sexes had the greater number of lesions in the polluted site than in the reference one. Also, there were no significant differences between sexes, neither within the same site/season nor between sites/seasons. Chi-square analysis of the difference between lesions per individual and aberrant cells per individual among sites showed that no site deviated from the expected difference (p=1.000). Developmental stability, assessed as FA, was reduced in the polluted area for two traits (width of lower jaw and length of the diastema lower jaw). Juvenile animals from the polluted area had significantly higher levels of FA compared to those from the reference site for three traits (length of the foramina incisiva, distance between incisor and the third upper molar, and length of the upper molars row). Juvenile animals from the polluted area had significantly higher levels of FA for three traits (length of the foramina incisiva, length of the lower molars row and width of lower jaw) compared to adult ones. In the polluted area seasonal differences were detected for two traits (length of the foramina incisiva and length of the upper molars row). Finally, Apodemus agrarius may be an important species for environmental quality evaluation studies based on an assay using a combination of end-points.

Variability Among Aflatoxin Test Results on Runner Peanuts Harvested From Small Field Plots1

Abstract An experiment was conducted to determine the variability associated with aflatoxin contamination of peanuts from plants grown in specified row lengths. Runner peanuts (cv. Georgia Green) were planted in 10, 76.2 m rows (20 seed/m) and grown using standard production practices. Plants were exposed to natural late-season drought conditions making the peanuts susceptible to preharvest aflatoxin contamination. Plants were mechanically dug, inverted, and separated into 500 plots of 1.5 m single rows. Peanuts from each numerically identified plot were harvested with a mechanical picker, dried to 8% kernel moisture (wet basis), shelled, and analyzed for aflatoxin by high performance liquid chromatography (HPLC). The average kernel mass and weighted average aflatoxin concentration for all plots was 131 g and 2278 ng/g, respectively. The kernel mass varied among the 500 plots from a low of 4 g to a maximum of 283 g. The aflatoxin concentration among the 500 plots varied from a low of 0 ng/g to a maximum of 32,142 ng/g. The standard deviation among the 500 plot aflatoxin values was 4061. The standard deviation among sample concentrations for this field study was very similar to previous studies that measured the standard deviation among sample concentrations taken from bulk farmers' stock lots. Increasing plot length decreased the standard deviation among plot aflatoxin values as predicted by statistical theory. For example, increasing plot row length by a factor of four, or from 1.5 to 6 m, decreased the standard deviation by a factor of two, or from 4061 to 2031. A regression equation was developed to predict the effect of plot row length on the variability among aflatoxin plot values. This information is useful for designing field plot experiments to test various strategies for reducing or preventing preharvest aflatoxin contamination.

Sex- and Age Related Differences in Tooth Row Length of Small Mammals: Mice

The article analyses sex- and age-related differences in tooth row length (TRL) in four vole species – bank vole (Clethrionomys glareolus), common vole (Microtus arvalis), root vole (M. oeconomus), and short-tailed vole (M. agrestis) – found in Lithuania and the correlation between their body weight, length, and TRL. Sexual dimorphism was found in M. oeconomus, in which body measurements and mandibular TRL were larger in females. The mandibular TRL was slightly larger in males of C. glareolus as well (p < 0.10). Age-related differences in the length of the maxillary and mandibular tooth row were found in all the three Microtus species. In C. glareolus, the maxillary and mandibular TRLs were shorter in young animals only. The correlation of the maxillary and mandibular TRL with the body weight and length was positive, strong and significant in Microtus voles. We outlined the limits of the maxillary and mandibular TRLs in these voles, within which it is possible to predict the age group of an individual, it...

Sex- and Age Related Differences in Tooth Row Length of Small Mammals: Shrews

Sex- and Age Related Differences in Tooth Row Length of Small Mammals: Shrews

Sex and Age Related Differences in Tooth Row Length of Small Mammals: Voles

Sex and Age Related Differences in Tooth Row Length of Small Mammals: Voles

Effect on yield and dry‐matter distribution of the stay‐green characteristic in cultivars of forage maize grown in England

AbstractTo test whether or not the ‘stay‐green’ (SG) characteristic confers benefits in terms of crop yield or distribution of dry matter (DM) in selected forage maize cultivars, an experiment was conducted in 1998 and 1999 at two sites in England: Writtle College, Essex and the University of Leeds, West Yorkshire. Five SG and five conventional (C) cultivars of forage maize were grown in replicated field‐scale plots at each site in both years. One‐metre lengths of single rows in each plot were harvested by hand, leaving a 20‐cm stubble, on four occasions each year over 3‐week periods (harvest 1 to harvest 4), prior to the harvest of the remainder of the fields. Plants were chopped, mixed and a subsample taken for determination of DM content by oven‐drying. Mean yields of whole plant DM were similar between SG and C cultivars. Both yield of DM and proportion of ear in the total plant DM increased from harvest 1 to harvest 4 (P &lt; 0·01). The increase in DM yield between harvest 1 and harvest 4 was greater for C than for SG cultivars (P &lt; 0·05). Within sites there were no differences in the concentration of whole plant DM between SG and C cultivars, which increased from harvest 1 to harvest 4 (P &lt; 0·001). The proportion of ear DM in the whole plant DM tended to be higher for C than for SG cultivars in both years and increased (P &lt; 0·001) from harvest 1 to harvest 4. The concentration of DM in the ear fraction was higher (P &lt; 0·05) for C than for SG cultivars. We conclude that differences between SG and C cultivars of forage maize are likely to be relatively small when grown in the English climate and harvested after the same growing period.

A generic method of pesticide dose expression: Application to broadcast spraying of apple trees

SummaryThe recommended dose for many pesticides is expressed as a constant mass or volume per unit ground area covered by the crop. This method of dose expression is well suited to boom spraying where a reasonably uniform horizontal distribution of deposit can be achieved with a well‐adjusted sprayer. However, in many practical situations (e.g. broadcast spraying of apple trees or other row structures where the spray application is made from within the canopy) the horizontal deposit distribution is strongly influenced by the crop area density and other crop structural parameters. This paper describes a generic method of pesticide dose expression to investigate these effects. The method incorporates a model of the spray volume deposition process. The model assumes that the pesticide deposit is proportional to the tank‐mix concentration of pesticide. The model also assumes that spray volume deposit is proportional to the applied spray volume per unit row length and is inversely proportional to a crop length scaling function L (i.e. a parameter with the units of length that is expressed as a generic function of different crop parameters). The useful working range of this model is bounded by the condition for high spray volume where target losses become significant due to saturation and the condition for very low volume where evaporative transport losses become significant. Within this framework, four different models are formulated using first‐order approximations for the length‐scale as functions of the following crop parameters: tree row spacing, tree row height, tree area density and tree row volume to ground area ratio. Published measurements of crop structure and spray volume deposit on apple trees are compared with the output from these models. Light detection and range (LIDAR) measurements of apple orchards are presented and used in conjunction with the different models to predict pesticide use associated with different methods of dose expression. The results demonstrate the relative potential for varying the pesticide application rate according to the different crop parameters. The results enable the identification of reference orchards that could be used to establish worst‐case pesticide application rates for registration purposes. The results also enable the identification of other orchards and growth stages where pesticide application rate might be reduced by up to a factor of five and give the same pesticide deposit as the reference structure.

Paleoecological reconstruction of a lower Pleistocene large mammal community using biogeochemical (δ13C, δ15N, δ18O, Sr:Zn) and ecomorphological approaches

Abstract Ecomorphological and biogeochemical (trace element, and carbon, nitrogen, and oxygen isotope ratios) analyses have been used for determining the dietary niches and habitat preferences of large mammals from lower Pleistocene deposits at Venta Micena (Guadix-Baza Basin, Spain). The combination of these two approaches takes advantage of the strengths and overcome the weakness of both approaches. The range of δ13Ccollagen values for ungulate species indicates that C3 plants were dominant in the diet of these mammals. δ13Ccollagen values vary among ungulates: perissodactyls have the lowest values and bovids the highest ones, with cervids showing intermediate values. The hypsodonty index measured in lower molar teeth and the relative length of the lower premolar tooth row indicate that the horse, Equus altidens, was a grazing species, whereas the rhino, Stephanorhinus etruscus, was a mixed feeder in open habitats. The similar δ13Ccollagen values shown in both perissodactyls does not reflect differences...

DEVELOPMENT OF AN AUTOMATED SYSTEM FOR SAMPLING CROP MATERIAL FROM A FORAGE HARVESTER

A modular, computercontrolled sampling system was developed to directly sample chopped forage material froma forage harvester spout. Pneumatic cylinders powered a deflector flap to redirect crop material from the spout. A hydrauliccylinder compressed deflected forage material into 35.6cm long, 10.2cm diameter PVC pipes, which served as miniaturetest silos. Timing of the pneumatic and hydraulic actuators was controlled by a programmable microcontroller. The controlsystem included three operator inputs: travel speed, row length, and number of samples along the row for each silo; thisprovided flexibility to adapt to different harvesting situations. In two experiments, testsilo samples fermented for 48 daysand then were separated into six size fractions. In the first experiment, a sidebyside comparison with a selfpropelled plotharvester, statistically significant differences in the mass fractions of medium and small particles (indicated by low pvaluesin the range of 0.1 to < 0.001) were found between samples collected by both machines and their respective controls. Nodifferences in the mass fractions of large particles were found. In the second experiment, the performance of the modularsampling system in sampling corn chopped at two theoretical lengths of cut (6.35 and 19.1 mm) and two wholeplant moisturelevels (approximately 70 and 60% w.b.) was evaluated. Some significant statistical differences between automatic samplingand manual sampling were present; however, trends were inconclusive. The magnitudes of mass percentage and characteristicparticle size differences were at most 8% and 1.6 mm, respectively.

Morphometric Data on the Field Ecotype Roe Deer in Southwest Lithuania

The formation process of the field ecotype of roe deer began in woodless (woods cover only 9% of the territory) flatlands of Southwest Lithuania with rich soil in 1965–1967. The field ecotype roe deer is heavier than the forest ecotype: the average weight of a juvenile male is 20.4 kg; juvenile female weighs 20.1 kg; yearling male – 26.3 kg; adult male – 31.0 kg; adult female – 27.7 kg. The cranium of the field ecotype of roebucks is larger too. Statistically significant differences were found in the total cranial length, length of nasals and length of the teeth row in maxilla. The cranium of the roe deer grows during the whole lifetime. The diameter of the burr shows the greatest augmentation (75%).

Paleoecological reconstruction of a lower Pleistocene large mammal community using biogeochemical (δ13C, δ15N, δ18O, Sr:Zn) and ecomorphological approaches

Ecomorphological and biogeochemical (trace element, and carbon, nitrogen, and oxygen isotope ratios) analyses have been used for determining the dietary niches and habitat preferences of large mammals from lower Pleistocene deposits at Venta Micena (Guadix-Baza Basin, Spain). The combination of these two approaches takes advantage of the strengths and overcome the weakness of both approaches. The range of δ13Ccollagen values for ungulate species indicates that C3 plants were dominant in the diet of these mammals. δ13Ccollagen values vary among ungulates: perissodactyls have the lowest values and bovids the highest ones, with cervids showing intermediate values. The hypsodonty index measured in lower molar teeth and the relative length of the lower premolar tooth row indicate that the horse, Equus altidens, was a grazing species, whereas the rhino, Stephanorhinus etruscus, was a mixed feeder in open habitats. The similar δ13Ccollagen values shown in both perissodactyls does not reflect differences in feeding behavior with other ungulates, but rather a lower isotope enrichment factor in these monogastric herbivores than in ruminants, owing to their lower metabolic efficiency. The cervids Eucladoceros giulii and Dama sp. show low hypsodonty values, indicating that they were mixed feeders or browsers from forested habitats, an ecomorphologically based conclusion corroborated in the former by its low δ15Ncollagen content (canopy effect). Bovid species (Bovini aff. Leptobos, Soergelia minor, and Hemitragus albus) presumably inhabited open environments, according to their comparatively high hypsodonty and δ15Ncollagen values. Carnivore species (Homotherium latidens, Megantereon whitei, Pachycrocuta brevirostris, Canis falconeri, and Canis etruscus) exhibit higher δ15Ncollagen values than ungulates. These results record the isotopic enrichment expected with an increase in trophic level and are also supported by low bone Sr.Zn ratios. The elevated δ15Ncollagen value for a sample of Mammuthus meridionalis, which came from an individual with unfused epiphyses, confirms that it was a suckling animal. The δ15Ncollagen value of the scimitar-cat H. latidens is well above that obtained for the young individual of Mammuthus, which indicates that juvenile elephants were an important part of its diet. The hippo, Hippopotamus antiquus, yielded unexpectedly high δ15Ncollagen values, which suggest feeding on aquatic, non-N2-fixing plants. The high δ18Ohydroxyl values of bovids Hemitragus and Soergelia and of cervid Dama indicate that these ungulates obtained most of their water requirements from the vegetation. The megaherbivores and Eucladoceros exhibit the lowest δ18Ohydroxyl values, which suggest increased water dependence for them. Paleosynecological analysis was based on the relative abundance of species of large mammals from different ecological categories, determined by feeding behavior and locomotion types. The comparison of the frequencies of such categories in Venta Micena with those found in modern African communities indicates that the composition of the paleocommunity closely resembles those of savannas with tall grass and shrubs. The net above-ground primary productivity estimated for the on-crop biomass of the mammalian species preserved in the fossil assemblage also yields a figure congruent with that expected for an open environment.

Relating potato yield and quality to field scale variability in soil characteristics

Causes of within-field spatial variability in potato (Solarium tuberosum L.) yield are not well understood. To address this, a study was conducted from 1998 to 2000 on a commercial farm in southeastern Washington. Soil samples were collected from four center-pivot-irrigated, uniformly fertilized fields on a 0.4-ha grid interval prior to potato planting and analyzed for nitrate-N, ammonium-N, P, K, organic matter, pH, and texture. The elevation of each grid point was also recorded. Four to five days before commercial harvest, potatoes were collected from a 3-m row length at each original grid point using a one-row digger. The potatoes were weighed, sorted into five weight classes, and evaluated for specific gravity. Correlation and stepwise regression analyses were conducted to test relationships between soil-based and yield variables. Factors driving yield varied between fields. Soil texture components (sand, silt, clay) had stronger impact on yield than with the soil chemical properties we measured. However, all four fields showed an inverse relationship between specific gravity and soil test K, although the correlation coefficients and contributions to regression models were relatively low. Finding a general prescription formula for goals other than higher yield (e.g., nutrient-leaching potential) may be feasible. The consistent relationship of soil textural components in our models suggest that monitoring available soil water, a factor closely related to soil texture, should be included in any future work.

Variation at high latitudes: the geography of body size and cranial morphology of the muskox, Ovibos moschatus

Abstract Aim Bergmann's rule, one of the most studied and controversial ecogeographical generalizations, has rarely been tested with observations from high latitudes. We tested the rule using cranial measurements of the muskox [Ovibos moschatus (Zimmerman)], a homeotherm with an extremely northern distribution. We also used these data to describe geographical patterns in the species' dental architecture, an extension of the framework developed from interspecific comparisons.Location Specimens were compiled from arctic Canada, Alaska and Greenland, a latitudinal range of 60° N−83° N.Methods Body size was estimated from principal components analysis (PCA) of five cranial characters from 128 specimens. Mean scores on the first principal component from each locality were regressed against latitude and mean temperature to identify geographical variation in body size; scores on the second principal component were regressed against latitude to assess patterns in dental architecture. Regression analyses of the individual characters were performed as a complement to PCA.Results No latitudinal or climatic trend in body size was observed in either sex. On the other hand, for males, significant latitudinal variation was found for the second PCA axis (r = −0.434), and the feature which loaded most heavily on it, maxillary tooth row length (r = 0.429). For females, this dental structure also tended to increase with latitude (r = 0.423), but the trend was only marginally significant (P=0.12), perhaps owing to a smaller sample size.Main conclusions The geographically invariant body size of muskoxen failed to support current hypotheses of size variation. Behavioural and physiological adaptations may exempt the muskox from selective pressures underlying these hypotheses. We interpret latitudinal variation in dental architecture as a reflection of a cline in diet, dominated by graminoids at the expense of willows at higher latitudes. This intraspecific geographical trend is a recapitulation of the interspecific framework for large mammalian herbivores.

IT—Information Technology and the Human Interface: Comparison of Different Spray Volume Deposition Models Using LIDAR Measurements of Apple Orchards

This paper reviews the models of spray volume deposition that have been developed to enable the adjustment of pesticide output from an axial fan sprayer to suit different apple orchards. The review has been limited to the empirical models of leaf deposit D formulated as D= Q/ UL, where L is a length-scale that describes the scaling effect of crop structure and Q/ U is the ratio of the spray volumetric flow rate to sprayer speed which defines the volume application rate on a per unit row length basis. The comparative performance of different models was evaluated using field measurements of leaf deposit on Cox apple trees with different combinations of rootstock, plantation density, age and growth stage. A tractor-mounted light detection and ranging (LIDAR) system was used to record orchard structural detail. Different methods for calculating the length-scale L from this information have been developed based on a range of different orchard crop structural parameters. Linear regression analysis of the measurements showed that the standard method of adjusting pesticide output, based on a linear scaling of the spray volume application rate per unit ground area, accounted for only 9% of the variation in the measurements. The use of other models, based on different geometric scaling parameters of orchard structure were demonstrated to give improved correlation with measurements. Of these models, the best correlation was obtained by using a length-scale proportional to the ratio of the tree volume to total ground area and this accounted for 43% of the variation in the measurements. The use of orchard structure parameters, based on crop area estimates derived from a local Poisson distribution of light transmission, gave further improvements. Of these models, the best correlation was obtained with a length-scale proportional to the tree area density and this accounted for 78% of the variation in the measurements. The tree area density is thus the best single crop structure parameter to use as the basis for pesticide dose expression for the practices of apple orchard spraying represented by these measurements. The calculation of this parameter relies on the availability of LIDAR measurements. Alternatively, a simple method for estimating this parameter might easily be constructed as a pictograph showing the relative tree area density associated with orchard tree images that can be reconstructed from these measurements. This research further identifies the need for this type of crop structural information to improve standardization of the dose recommendations on pesticide labels.

Relative Performance of Soybean in End‐Trimmed and Plant‐to‐Length Plots

A common method to reduce or eliminate potential end‐row effects in yield trials is to remove a portion of the plants from the end of the row prior to harvest. Consistent evidence supporting or rejecting the need to end‐trim field plots is not available. This study was conducted to determine if plots planted to harvest length and not end‐trimmed could be substituted for end‐trimmed plots without affecting adversely the relative yield performance of entries in a trial. During 1997 and 1998, separate trials of soybean [Glycine max (L.) Merr.] genotypes in maturity groups III, IV, and V were evaluated in four‐row plots at three locations with three replications per location. In each trial, 20 entries were evaluated using three plot treatments: (i) a plot planted to a harvest length of 4.6 m, (ii) a 4.6 m plot end‐trimmed to a harvest length of 3.8 m during early vegetative development, and (iii) a 4.6‐m plot end‐trimmed to a harvest length of 3.8 m following maturity. Seed yield and row length were determined for each plot. Seed yields were significantly different among entries for all three trials. The interactions of plot treatment by entry within year and of plot treatment by entry by location within year were not significant for seed yield in all three trials. Plots planted to harvest length provided an unbiased estimate of the relative performance of yield in soybean.

Plant maturity and kenaf yield components

Kenaf ( Hibiscus cannabinus L.), an alternative fiber crop for paper pulp production, is normally grown during the entire summer growing season (150 days and longer) to maximize fiber production. However, it may be advantageous to harvest the kenaf crop earlier than 150 days after planting (DAP) depending on the harvesting conditions (e.g. soil moisture or equipment availability) or marketing opportunities (price fluctuations or alternative uses). In addition to affecting the final stalk yield, harvesting kenaf at an earlier maturity may significantly alter the composition of the kenaf plant. The objective of this field study was to determine the effect of kenaf plant maturity on kenaf yield components. Kenaf cultivar ‘Everglades 41’ was planted at Lane, Oklahoma, USA, in the spring of 1996, 1997, and 1998 on 76 cm row spacing at 250 000 plants per hecatre. Kenaf plots were harvested at four harvest dates, 60, 90, 120, and 150 DAP. At each harvest date, plants from a 3 m length of row were cut at ground level and used to determine plant population, plant height, stalk, leaf and whole plant yields, stalk and leaf percentage by weight, and the rate of plant growth during the selected growing season. The experiment was a randomized complete block design with five replications. Harvest age (60, 90, 120, and 150 DAP) did not significantly affect plant populations, but significantly affected all other yield parameters. Kenaf plant height, stalk yield, stalk percentage, and total plant biomass yields were consistently significantly greater at 150 DAP than at 60, 90, and 120 DAP for the 3 year study. Although the growth rates per day did level off or even decreased after 120 DAP, the significant increases in stalk yields after 120 DAP justify the additional 30 day growth. This research provides information that can be applied to both kenaf fiber and forage production, especially in gaining a greater understanding of the relative response of the kenaf yield components and partitioning of dry matter during the growing season. The research procedures can also be used for evaluating kenaf cultivars that may be more suitable for forage production, by identifying cultivars that have greater leaf biomass yields and leaf percentages earlier in the season and increasing values throughout the growing season.

Relative Performance of Soybean in End-Trimmed and Plant-to-Length Plots

A common method to reduce or eliminate potential end-row effects in yield trials is to remove a portion of the plants from the end of the row prior to harvest. Consistent evidence supporting or rejecting the need to end-trim field plots is not available. This study was conducted to determine if plots planted to harvest length and not end-trimmed could be substituted for end-trimmed plots without affecting adversely the relative yield performance of entries in a trial. During 1997 and 1998, separate trials of soybean [Glycine max (L.) Merr.] genotypes in maturity groups III, IV, and V were evaluated in four-row plots at three locations with three replications per location. In each trial, 20 entries were evaluated using three plot treatments: (i) a plot planted to a harvest length of 4.6 m, (ii) a 4.6 m plot end-trimmed to a harvest length of 3.8 m during early vegetative development, and (iii) a 4.6-m plot end-trimmed to a harvest length of 3.8 m following maturity. Seed yield and row length were determined for each plot. Seed yields were significantly different among entries for all three trials. The interactions of plot treatment by entry within year and of plot treatment by entry by location within year were not significant for seed yield in all three trials. Plots planted to harvest length provided an unbiased estimate of the relative performance of yield in soybean.

Dietary adaptations of extant and Neogene African suids

AbstractPlio‐Pleistocene suid assemblages of sub‐Saharan Africa seem to have been derived from the immigration of Asian tetraconodontines during the late Miocene and of Asian suines in the mid Pliocene. Lineages of both subfamilies display evolutionary changes that decrease the length of the premolar row and increase the length, height and complexity of the molars. Such changes have proved useful for estimating the relative ages of the sites from which suid fossils have been retrieved. They have also been used for interpreting the probable habitat and as evidence of environmental change through time. Isotopic analyses of tooth enamel from extant suid species generally confirm field observations of their dietary preferences. Similar analyses of suid dental enamel from Neogene localities of eastern Africa provide information that partly supports previous interpretations of the diets of extinct suid species. The increase in size and complexity of nyanzachoere teeth reflects their exploitation of C4 vegetation, although the nyanzachoeres did not acquire their grazing habits until after contemporary perissodactyls and proboscideans had become dedicated C4 grazers. In contrast to earlier interpretations, kolpochoeres and metridiochoeres were already dedicated grazers by the time they became significant components of the East African biota. Like their living counterparts, the warthogs and forest hogs, metridiochoeres were less water‐dependent than kolpochoeres.