湾鳄人工饲养的几个常用技术操作

以成都动物园人工饲养的7条湾鳄Crocodylus porosus Schneider为对象,介绍了在人工饲养条件下经常会用到的抓捕、采血、性别鉴定等技术操作及其意义,为湾鳄的人工饲养管理提供一定的实践依据.     

人鳄一体的木乃伊

埃及的木乃伊 ,被考古学家挖出研究的不下五万具。１８５１年 ,法国考古学家奥丘斯·马里埃在开罗近郊的地下 ,发掘出了一座巨大的陵墓。陵墓是用精工磨制的黑红相间的花岗岩砌成的。在数千斤重的石棺中 ,人们惊奇地看到一具牛的木乃伊卧在其中。大约５０００年前 ,埃及人把努比亚野生猫和山猫杂交 ,得到了新变种。由于新种猫特别能吃老鼠 ,所以受到埃及人的保护和崇拜 ,在神殿里铸造了各种神态的青铜猫。猫死了 ,还要制成木乃伊 ,涂以香料 ,隆重下葬。１８６０年 ,在埃及的别尼哈桑发现了古埃及的猫的墓地 ,这里竟埋葬着１８万只猫的木乃伊…     

鳄类的繁殖生物学特性

概述了鳄类动物的繁殖生物学特性。对在其它爬行动物中不多见,而在鳄类中普遍存在的亲体关怀行为和孵化温度决定后代性别的现象进行了阐述。并从生态学和进化论角度,对这些现象进行了讨论。     

西蜀鳄(Hsisosuchus)的系统发育关系

本文简介了分支系统学意义上的鳄型动物（CrocodylomorphaWalker．1970）的组成。首次应用分支系统学方法讨论了重庆西蜀鳄的系统发有关系。本文的结论否定了西蜀鳄和西贝鳄类系统关系相近的论点,并认为前者比后者要原始得多,它是Mesoeucrocodylia中最原始的代表之一。     

湾鳄人工孵化的初步研究

本文报道了１９９７～１９９８年湾鳄（Ｃｒｏｃｏｄｙｌｕｓｐｏｒｏｓｕｓ）的人工孵化工作,并通过对比试验确定了鳄卵孵化的最适温度、湿度以及最佳的覆盖巢材和鳄卵在孵化盘中的正确摆放方位。获得受精卵总孵化率为８６－８％。１　材料方法试验用卵取自深圳市野生动物园湾鳄产下的卵。将所有收集到的未破损的受精卵分成２组,一组为湾鳄在人工设置的产卵间内自然营巢产的卵,按母鳄产卵时自然摆放的方位放入盛卵盘内作为正放组;另一组为没有营巢环境而产于水泥地或草地上的滚动过的卵作为对照组。２　结　果２－１　１９９７年有３条…     

鳄与人

“看,它冲出菖蒲和芦苇丛,腹部滚圆,高高地甩着那满是褶皱的尾巴,漂浮在湖面上。血盆大口处,水流如瀑;宽阔鼻孔中,雾气滚滚。大地在它脚下颤抖,发出雷鸣般的声音。”     

鳄类的取食和繁殖行为

鳄类是现代爬行动物中身体结构最高级的动物,就其捕食,求偶与交配,营巢与产卵,护巢,挖巢和护幼等行为进行了介绍。     

湾鳄采食量活动性季节变化与环境温度的关系

湾鳄是外热动物,其采食量及活动规律受环境温度的影响极为明显,呈现苏醒期、发情期、产蛋繁殖期（盛食期）,越冬准确期,越冬期等季节性周期现象。越冬期人工保温,是提高湾鳄成活率的关键。     

一龄内扬子鳄的饲养和管理技术的改进

对扬子鳄幼鳄的饲养与管理技术进行了改进,经过1996－1998年计5000多条幼鳄的饲养实践,总结出新的饲养与管理技术,对提高幼鳄的成活具有极为显著的效果,8月龄成活率可达95％左右,14月龄成活率90％左右。     

为什么要保护鳄类

<正>许多人问道:"怎么会有人对保护鳄鱼感兴趣?它们的相貌那么可怕、邪恶,还富有攻击性,为什么还要保护它们呢?"其实,鳄类是地球上现存的几种最令人称奇的动物之一,是除海洋生物以外世界上最大的食肉动物,它们当中有些种类身长超过6米,体重超过1吨。一条成年鳄类在水中可以与一匹成年斑马抗     

FAIR TRADE INTERNATIONAL SURROGACY

Since the development of assisted reproductive technologies, infertile individuals have crossed borders to obtain treatments unavailable or unaffordable in their own country. Recent media coverage has focused on the outsourcing of surrogacy to developing countries, where the cost for surrogacy is significantly less than the equivalent cost in a more developed country. This paper discusses the ethical arguments against international surrogacy. The major opposition viewpoints can be broadly divided into arguments about welfare, commodification and exploitation.
It is argued that the only valid objection to international surrogacy is that surrogate mothers may be exploited by being given too little compensation. However, the possibility of exploitation is a weak argument for prohibition, as employment alternatives for potential surrogate mothers may be more exploitative or more harmful than surrogacy. It is concluded that international surrogacy must be regulated, and the proposed regulatory mechanism is termed Fair Trade Surrogacy. The guidelines of Fair Trade Surrogacy focus on minimizing potential harms to all parties and ensuring fair compensation for surrogate mothers.     

扬子鳄皮肤腺结构与发育的初步观察

扬子鳄有三种皮肤腺:背腺、泄殖腔麝腺和下颌腺。背腺位于背中线左右两侧第二行鳞片下方,其确切位置个体间差异很大,如表1。幼鳄背腺形态多种多样,但显示出是一种退化器官,未观察到腺开口,也未观察到半成鳄和成鳄的背腺,因此扬子鳄背腺可能不具功能。泄殖腔麝腺位于泄殖腔腹唇内,梨形,腺管开口于泄殖腔腹壁,成体腺腔很大,腺的底部壁较厚,腺细胞明显地分成若干小叶,其它部位壁较薄,小叶不明显,属全泌腺,分泌油脂物,繁殖期特别发达,但性未成熟个体亦具功能,是一种信息素下颌腺位于下颌后方两侧皮肤内,圆柱状,脉管开口于下颌腹侧皮肤表面,成体腺腔不规则,腺壁厚,从包囊到腺腔,腺细胞可明显地分成三个区,属全泌腺,分泌油脂物,在繁殖期特别发达,此腺到性成熟才具功能。     

扬子鳄胃的组织化学及超微结构研究

爬行动物胃的一般组织学和组织化学的研究资料较多,Luppa1对此作了较为详细的总结.超微结构方面,龟鳖类和蜥蜴类亦有报道2,3,鳄类的资料尚缺.扬子鳄(Alligator sinensisFuval)是我国现存惟一的特有鳄类,陈壁辉4等曾对其食性进行了细致的考察,也对胃的一般组织结构作了描述.作者拟从组织化学和超微结构方面对扬子鳄的胃作进一步的研究,以丰富比较组织和细胞学资料,同时也增进对扬子鳄进化位置及其食性适应性结构的认识.       

扬子鳄的现状与保护

扬子鳄为我国特有的珍稀爬行动物,被我国政府列为国家一级保护,在我国有关它的记载已有三千多年的历史。古典文献把它记作“鼍’,民间称为“土龙”、“猪婆龙”,拉丁学名叫Alligatorsinensis。据史料记载,约五百多年前,它在长江中下游种群分布稠密,分布区范围约在东经11     

THE DUTY TO DIE AND THE BURDENSOMENESS OF LIVING

This article addresses the question of whether the arguments for a duty to die given by John Hardwig, the most prominent philosophical advocate of such a duty, are sound. Hardwig believes that the duty to die is relatively widespread among those with burdensome illnesses, dependencies, or medical conditions. I argue that although there are rare circumstances in which individuals have a duty to die, the situations Hardwig describes are not among these. After reconstructing Hardwig's argument for such a duty, highlighting his central premise that ill, dependent, or aged individuals can impose unfair burdens upon others by continuing to live, I clarify precisely what Hardwig intends by his thesis that many of us have a duty to die. I then show that an important disanalogy exists between an uncontroversial example in which an individual has a duty to die and the situations in which Hardwig proposes individuals have a duty to die. More specifically, in situations where a duty to die exists, an individual's having a duty to die logically implies that those she burdens have a right to kill that individual in self‐defense. I then suggest that the burdens that ill, dependent, or aged individuals impose on their families, loved ones, or caregivers do not constitute the kind of threat that warrants the latter killing the former in self‐defense. Hence, the duty to die is much rarer than Hardwig supposes.